Keyboard works in front USB ports but not back ones

[-Psy-]

This is weird. I unplugged my PC because me and my Dad had planned to start upgrading it but we decided to postpone it to another night. So, I plugged everything back in the usual places, turn the computer on and everything is fine but...the keyboard doesn't work once Windows loads up. It worked fine before the Windows loading screen because I can go to the BIOS so I'm guessing this is some kind of driver issue.

So now I've got the keyboard plugged into one of the front USB ports and it's working perfectly fine. Any ideas? :/