Map Caps-Lock to Control in Windows 8.1
Using regedit is the best way imo as you know it works. This will make caps-lock an additional ctrl. But won't mess with ctrl itself.
For windows 7 and 8 do the following:
Open regedit.exe
Go to this directory (in regedit):
~/HKEY_LOCAL_MACHINE/SYSTEM/CurrentControlSet/Control/KeyboardLayout/
After clicking on that directory (KeyboardLayout) right click in the right box and add new Binary Value
called 'Scancode Map'
For windows 7 write this:
00 00 00 00 00 00 00 00
02 00 00 00 1D 00 3A 00
00 00 00 00
For windows 8 write this, I have verified that this works on 8.1 and 10 (this is just four extra zeros):
00 00 00 00 00 00 00 00
02 00 00 00 1D 00 3A 00
00 00 00 00 00 00 00 00
Hit okay and reboot.
SharpKeys did it for me! I couldn't find any other way and as you've discovered the old registry hack doesn't work anymore :(
http://sharpkeys.codeplex.com/