- Open Regedit.exe (Start->Run: regedit or Type regedit in the Windows 7 "Awesome Bar")
- Browse in the Registry Editor to: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Keyboard Layout
- Click Edit->New->Binary Value and name it "Scancode Map"
- Double click Scancode Map and set the value to:
00,00,00,00, 00,00,00,00, 02,00,00,00, 1d,00,3A,00, 00,00,00,00
Thats it! After restarting your computer your Capslock key will function as a Control key instead.
For a more in depth look at key remapping in Windows please see this How-To-Geek article.