diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..5e6607e
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,2 @@
+*.exe
+*.log
diff --git a/README.md b/README.md
index 9229581..a43269b 100644
--- a/README.md
+++ b/README.md
@@ -1,3 +1,38 @@
 # autoPriority
 
-A program that automatically sets a high priority for game processes
\ No newline at end of file
+Automatically sets high CPU priority for memory-heavy processes.
+
+## Build
+
+```
+# Standard build (with console window)
+go build -o autopriority.exe .
+
+# Background build (no console, minimal size)
+go build -ldflags="-H windowsgui -s -w" -o autopriority.exe .
+```
+
+## Usage
+
+```
+autopriority [flags]
+```
+
+| Flag        | Default       | Description                      |
+|-------------|---------------|----------------------------------|
+| `-mem`      | 536870912     | Memory threshold in bytes        |
+| `-interval` | 1m0s          | Scan interval (min 10s)          |
+| `-dry-run`  | false         | Log only, don't change priority  |
+| `-log`      | true          | Write `autopriority.log` file    |
+
+## Auto-start
+
+Place a shortcut to `autopriority.exe` in:
+
+```
+shell:startup
+```
+
+## Dependencies
+
+None. Uses only Windows API (kernel32, psapi) via raw syscall.
diff --git a/go.mod b/go.mod
index b9c8282..7b79382 100644
--- a/go.mod
+++ b/go.mod
@@ -1,13 +1,3 @@
-module autoPriority
+module autopriority
 
-go 1.19
-
-require (
-	github.com/go-ole/go-ole v1.2.6 // indirect
-	github.com/postfinance/single v0.0.2 // indirect
-	github.com/shirou/gopsutil v3.21.11+incompatible // indirect
-	github.com/tklauser/go-sysconf v0.3.11 // indirect
-	github.com/tklauser/numcpus v0.6.0 // indirect
-	github.com/yusufpapurcu/wmi v1.2.2 // indirect
-	golang.org/x/sys v0.4.0
-)
+go 1.24
diff --git a/go.sum b/go.sum
deleted file mode 100644
index 4664a37..0000000
--- a/go.sum
+++ /dev/null
@@ -1,22 +0,0 @@
-github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
-github.com/go-ole/go-ole v1.2.6 h1:/Fpf6oFPoeFik9ty7siob0G6Ke8QvQEuVcuChpwXzpY=
-github.com/go-ole/go-ole v1.2.6/go.mod h1:pprOEPIfldk/42T2oK7lQ4v4JSDwmV0As9GaiUsvbm0=
-github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
-github.com/postfinance/single v0.0.2 h1:YLjLxxeGDnsW93oK4CxxOFSVOOiBi1OyoK4ZTl5biJw=
-github.com/postfinance/single v0.0.2/go.mod h1:OYWUsdMIZK9eQyZYpAsMHN+j6+jXJ6RFUNqIWH0oC5U=
-github.com/shirou/gopsutil v3.21.11+incompatible h1:+1+c1VGhc88SSonWP6foOcLhvnKlUeu/erjjvaPEYiI=
-github.com/shirou/gopsutil v3.21.11+incompatible/go.mod h1:5b4v6he4MtMOwMlS0TUMTu2PcXUg8+E1lC7eC3UO/RA=
-github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
-github.com/stretchr/testify v1.7.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
-github.com/tklauser/go-sysconf v0.3.11 h1:89WgdJhk5SNwJfu+GKyYveZ4IaJ7xAkecBo+KdJV0CM=
-github.com/tklauser/go-sysconf v0.3.11/go.mod h1:GqXfhXY3kiPa0nAXPDIQIWzJbMCB7AmcWpGR8lSZfqI=
-github.com/tklauser/numcpus v0.6.0 h1:kebhY2Qt+3U6RNK7UqpYNA+tJ23IBEGKkB7JQBfDYms=
-github.com/tklauser/numcpus v0.6.0/go.mod h1:FEZLMke0lhOUG6w2JadTzp0a+Nl8PF/GFkQ5UVIcaL4=
-github.com/yusufpapurcu/wmi v1.2.2 h1:KBNDSne4vP5mbSWnJbO+51IMOXJB67QiYCSBrubbPRg=
-github.com/yusufpapurcu/wmi v1.2.2/go.mod h1:SBZ9tNy3G9/m5Oi98Zks0QjeHVDvuK0qfxQmPyzfmi0=
-golang.org/x/sys v0.0.0-20190916202348-b4ddaad3f8a3/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
-golang.org/x/sys v0.2.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.4.0 h1:Zr2JFtRQNX3BCZ8YtxRE9hNJYC8J6I1MVbMg6owUp18=
-golang.org/x/sys v0.4.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
-gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
diff --git a/main.go b/main.go
new file mode 100644
index 0000000..85c0378
--- /dev/null
+++ b/main.go
@@ -0,0 +1,262 @@
+//go:build windows
+
+package main
+
+import (
+	"flag"
+	"fmt"
+	"os"
+	"path/filepath"
+	"syscall"
+	"time"
+	"unsafe"
+)
+
+var (
+	k32 = syscall.NewLazyDLL("kernel32.dll")
+	ps  = syscall.NewLazyDLL("psapi.dll")
+
+	pCreateSnap     = k32.NewProc("CreateToolhelp32Snapshot")
+	pProcess32First = k32.NewProc("Process32FirstW")
+	pProcess32Next  = k32.NewProc("Process32NextW")
+	pGetProcMemInfo = ps.NewProc("GetProcessMemoryInfo")
+	pSetPriority    = k32.NewProc("SetPriorityClass")
+	pGetPriority    = k32.NewProc("GetPriorityClass")
+	pOpenProcess    = k32.NewProc("OpenProcess")
+	pCloseHandle    = k32.NewProc("CloseHandle")
+	pCreateMutex    = k32.NewProc("CreateMutexW")
+	pMessageBox     = k32.NewProc("MessageBoxW")
+	pGetLastError   = k32.NewProc("GetLastError")
+)
+
+const (
+	SNAPPROCESS = 0x00000002
+	SET_INFO    = 0x0200
+	QUERY_INFO  = 0x0400
+	IDLE_PRIO   = 0x00000040
+	NORMAL_PRIO = 0x00000020
+	HIGH_PRIO   = 0x00000080
+	EXISTING    = 1832
+)
+
+type pe32 struct {
+	Size      uint32
+	CntUsage  uint32
+	PID       uint32
+	HeapID    uintptr
+	ModuleID  uint32
+	Threads   uint32
+	ParentPID uint32
+	PrioClass int32
+	Flags     uint32
+	ExeFile   [260]uint16
+}
+
+type pmc struct {
+	CBM         uint32
+	PageFaults  uint32
+	PeakWS      uintptr
+	WorkingSet  uintptr
+	QuotaPeakPG uintptr
+	QuotaPG     uintptr
+	QuotaPeakPM uintptr
+	QuotaPM     uintptr
+	PeakPF      uintptr
+	Pagefile    uintptr
+	Reserved    [2]uintptr
+}
+
+type procInfo struct {
+	PID uint32
+	Name string
+}
+
+func wide(s string) *uint16 {
+	return syscall.StringToUTF16Ptr(s)
+}
+
+func closeH(h syscall.Handle) {
+	_, _, _ = pCloseHandle.Call(uintptr(h))
+}
+
+func openProc(pid uint32, acc uint32) syscall.Handle {
+	r, _, _ := pOpenProcess.Call(uintptr(acc), 0, uintptr(pid))
+	return syscall.Handle(r)
+}
+
+func setPrio(pid uint32, cls uint32) bool {
+	h := openProc(pid, SET_INFO)
+	if h == 0 {
+		return false
+	}
+	defer closeH(h)
+	r, _, _ := pSetPriority.Call(uintptr(h), uintptr(cls))
+	return r != 0
+}
+
+func curPrio(pid uint32) uint32 {
+	h := openProc(pid, QUERY_INFO)
+	if h == 0 {
+		return 0
+	}
+	defer closeH(h)
+	r, _, _ := pGetPriority.Call(uintptr(h))
+	return uint32(r)
+}
+
+func rss(pid uint32) uint64 {
+	h := openProc(pid, QUERY_INFO)
+	if h == 0 {
+		return 0
+	}
+	defer closeH(h)
+
+	var m pmc
+	r, _, _ := pGetProcMemInfo.Call(uintptr(h), uintptr(unsafe.Pointer(&m)), uintptr(unsafe.Sizeof(m)))
+	if r == 0 {
+		return 0
+	}
+	return uint64(m.WorkingSet)
+}
+
+func allProcs() []procInfo {
+	var out []procInfo
+	pe := pe32{Size: uint32(unsafe.Sizeof(pe32{}))}
+	snap, _, _ := pCreateSnap.Call(SNAPPROCESS, 0)
+	if snap == 0 {
+		return out
+	}
+	defer closeH(syscall.Handle(snap))
+
+	r, _, _ := pProcess32First.Call(snap, uintptr(unsafe.Pointer(&pe)))
+	if r != 0 {
+		for {
+			out = append(out, procInfo{
+				PID:  pe.PID,
+				Name: syscall.UTF16ToString(pe.ExeFile[:]),
+			})
+			r, _, _ := pProcess32Next.Call(snap, uintptr(unsafe.Pointer(&pe)))
+			if r == 0 {
+				break
+			}
+		}
+	}
+	return out
+}
+
+func prioName(c uint32) string {
+	switch c {
+	case IDLE_PRIO:
+		return "IDLE"
+	case NORMAL_PRIO:
+		return "NORMAL"
+	case HIGH_PRIO:
+		return "HIGH"
+	default:
+		return fmt.Sprintf("0x%X", c)
+	}
+}
+
+func main() {
+	mem := flag.Uint64("mem", 512*1024*1024, "memory threshold in bytes")
+	interval := flag.Duration("interval", time.Minute, "scan interval")
+	dryRun := flag.Bool("dry-run", false, "log only, do not change priorities")
+	doLog := flag.Bool("log", true, "write log file next to executable")
+	flag.Parse()
+
+	if *interval < 10*time.Second {
+		*interval = 10 * time.Second
+	}
+
+	var logFile *os.File
+	if *doLog {
+		exePath, _ := os.Executable()
+		f, err := os.OpenFile(filepath.Join(filepath.Dir(exePath), "autopriority.log"),
+			os.O_CREATE|os.O_WRONLY|os.O_TRUNC, 0644)
+		if err == nil {
+			logFile = f
+			defer logFile.Close()
+		}
+	}
+
+	ts := func() string {
+		return time.Now().Format("02.01.2006 15:04:05")
+	}
+
+	logf := func(format string, a ...any) {
+		if logFile == nil {
+			return
+		}
+		fmt.Fprintf(logFile, "[%s] ", ts())
+		fmt.Fprintf(logFile, format+"\n", a...)
+	}
+
+	logf("autoPriority started (mem=%d bytes, interval=%s, dry-run=%v)", *mem, *interval, *dryRun)
+
+	// Single instance
+	mh, _, _ := pCreateMutex.Call(0, 0, uintptr(unsafe.Pointer(wide("Global\\autopriority_v1"))))
+	lastErr, _, _ := pGetLastError.Call()
+	if lastErr == uintptr(EXISTING) {
+		closeH(syscall.Handle(mh))
+		pMessageBox.Call(0,
+			uintptr(unsafe.Pointer(wide("autoPriority is already running."))),
+			uintptr(unsafe.Pointer(wide("autoPriority"))),
+			0x30,
+		)
+		os.Exit(1)
+	}
+
+	// Lower own priority
+	pSetPriority.Call(uintptr(syscall.Handle(^uintptr(0))), IDLE_PRIO)
+	logf("own priority set to IDLE")
+
+	// promoted: PID → name (for restore logging)
+	promoted := make(map[uint32]string)
+
+	// Restore on exit
+	defer func() {
+		for pid, name := range promoted {
+			if setPrio(pid, NORMAL_PRIO) {
+				logf("RESTORE %s (PID %d) → NORMAL", name, pid)
+			}
+		}
+		logf("autoPriority stopped")
+	}()
+
+	myPID := uint32(os.Getpid())
+	ticker := time.NewTicker(*interval)
+	defer ticker.Stop()
+
+	scan := func() {
+		for _, p := range allProcs() {
+			if p.PID == myPID || p.PID == 0 {
+				continue
+			}
+			if _, ok := promoted[p.PID]; ok {
+				continue
+			}
+			if rss(p.PID) < *mem {
+				continue
+			}
+
+			orig := curPrio(p.PID)
+
+			if *dryRun {
+				logf("[DRY-RUN] %s (PID %d) RSS=%dMB, priority=%s — would set HIGH",
+					p.Name, p.PID, rss(p.PID)/1024/1024, prioName(orig))
+				continue
+			}
+
+			if setPrio(p.PID, HIGH_PRIO) {
+				promoted[p.PID] = p.Name
+				logf("PROMOTE %s (PID %d) RSS=%dMB, %s → HIGH",
+					p.Name, p.PID, rss(p.PID)/1024/1024, prioName(orig))
+			}
+		}
+	}
+
+	scan()
+	for range ticker.C {
+		scan()
+	}
+}
diff --git a/main_windows.go b/main_windows.go
deleted file mode 100644
index d96af06..0000000
--- a/main_windows.go
+++ /dev/null
@@ -1,79 +0,0 @@
-package main
-
-import (
-	"fmt"
-	"log"
-	"os"
-	"os/signal"
-	"time"
-
-	"github.com/postfinance/single"
-	"github.com/shirou/gopsutil/process"
-	"golang.org/x/sys/windows"
-)
-
-const (
-	memThreshold   = 512 * 1024 * 1024
-	selfPriority   = windows.IDLE_PRIORITY_CLASS
-	targetPriority = windows.HIGH_PRIORITY_CLASS
-)
-
-func setPriority(pid int32, class uint32) error {
-	h, err := windows.OpenProcess(windows.PROCESS_SET_INFORMATION, false, uint32(pid))
-	if err != nil {
-		return fmt.Errorf("open process %d: %w", pid, err)
-	}
-	defer windows.CloseHandle(h)
-	return windows.SetPriorityClass(h, class)
-}
-
-func main() {
-	lock, err := single.New("autoPriority")
-	if err != nil {
-		log.Fatalf("create lock: %v", err)
-	}
-	if err := lock.Lock(); err != nil {
-		windows.MessageBox(0,
-			windows.StringToUTF16Ptr("The program is already running.\nYou can close it via the Task Manager."),
-			windows.StringToUTF16Ptr("autoPriority"),
-			windows.MB_OK|windows.MB_ICONWARNING,
-		)
-		os.Exit(1)
-	}
-	defer lock.Unlock()
-
-	if err := setPriority(int32(os.Getpid()), selfPriority); err != nil {
-		log.Printf("set self priority: %v", err)
-	}
-
-	sig := make(chan os.Signal, 1)
-	signal.Notify(sig, os.Interrupt)
-
-	tk := time.NewTicker(time.Minute)
-	defer tk.Stop()
-
-	for {
-		select {
-		case <-sig:
-			log.Println("exit")
-			return
-		case <-tk.C:
-			procs, err := process.Processes()
-			if err != nil {
-				log.Printf("list processes: %v", err)
-				continue
-			}
-			for _, p := range procs {
-				m, err := p.MemoryInfo()
-				if err != nil {
-					continue
-				}
-				if m.RSS >= memThreshold {
-					if err := setPriority(p.Pid, targetPriority); err != nil {
-						log.Printf("PID %d: %v", p.Pid, err)
-					}
-				}
-			}
-		}
-	}
-}