Okay, so recently i have installed windows 7 and after setup, keyboard and mouse aren't working anymore. I have to mention that i have a PS/2 keyboard that i managed to get working.I entered in Device Manager and at Other devices, three Universal Serial B7s controllers are with an exclamation mark, with PCi Device and Ethernet controller.
My motherboard is a A320-S2H and my cpu Athlon 200GE.
Since you don't have functioning network or USB you need to do something else here. Try booting off a Linux Live disk, then download the drivers to the computer. Boot into Windows 7, run the drivers from the location you downloaded them to.