Everything was functioning properly. I turned my computer off and came back to it a couple of days later to find that the keyboard and mouse are not working in Windows.

I am running Windows 7, 64 bit. To see if this was a Windows problem, I checked to see if the keyboard and mouse still work in the BIOS, and they do perfectly:
The keyboard is one of those fancy (lights, macros and all that stuff) keyboards. When I turn on the computer and enter BIOS the keyboard lights up like it should with all the keys lit. The mouse which also has a special green light on top of it also does.

But when Windows boots up, during the windows loading logo screen the keyboard and mouse lights suddenly all turn off, then the login screen appears and suddenly only some of the keyboard buttons light up faintly, as if the keyboard is getting power but not enough.

I am currently using a PS/2 keyboard to type this, and it works perfectly.

Connecting and disconnecting the mouse or the keyboard to a different USB port (I tried USB2 and USB3) makes Windows try to install (or search?) for drivers, then if fails and gives me this window:

If you can't see the image for some reason or for the search engines, it's a window that says:
"Driver Software Installation. Device driver software was not successfully installed. Please consult with your device manufacturer for assistance getting this device installed. USB Composite Device Failed."

Windows will also sometimes do this right after I log in.

I tried Googling for hours and saw that people also have the same general problem (works in BIOS, not in Windows) and I tried all the solutions I could find (removing all power for the PC, resetting BIOS settings, Windows Update stuff, etc.).

Any help on how to solve this problem will be appreciated.

Thanks.