The CapsLock key is rubbish. Remapping it to Control is easy on OS X and the Happy Hacker keyboard I use on my desktops doesn’t even have one. On standard Windows you can run a key remapping program but WinRT is locked down (for now). Here is an easy way to map Caps Lock to Control.
First, hit the Windows key and type “Powershell”. Right click on the Powershell icon. You will see some options appear at the bottom of the screen – click “Run as Administrator. Agree to the UAC elevation prompt.
The elevated Powershell prompt will appear. You need to enter the following command and hit Enter:
Set-ItemProperty -path "HKLM:\SYSTEM\CurrentControlSet\Control\Keyboard Layout" -name "Scancode Map" -Value ([byte](0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x02,0x00,0x00,0x00,0x1d,0x00,0x3a,0x00,0x00,0x00,0x00,0x00))
This sets up some keyboard scancode remapping in the Registry, which is what keyboard remapping programs would do if they had access. Restart the machine (swipe from right, Settings Charm, power, Restart) to make the change take effect.
Good riddance Caps Lock!