This does not compile.

btkeytool.go

package main

import (
	"fmt"

	"golang.org/x/sys/windows/registry"
)

func main() {
	winversion, err := registry.OpenKey(registry.LOCAL_MACHINE, `SOFTWARE\Microsoft\Windows NT\CurrentVersion`, registry.QUERY_VALUE)
	if err == nil {
		fmt.Printf("Hello world! %v\n", winversion)
	} else {
		fmt.Printf("Hello, error.\n")
	}
}