USB problems in Windows 7

I have a Dell Dimension 3100 and I recently upgraded to windows 7 home premium (32 bit). Everything was working well until this morning when i discovered that none of my USB devices were working, that includes keyboard, mouse and everything needed to use my PC and no replacements work, it does not register any USB devices in the OS although the keyboard does strangely still work in DOS. I followed some suggestions on the internet and took out the CMOS battery on the motherboard and stuck it back in again. Unfortunately this didn't help but i did find that that one of my usb devices is broken on the inside possibly because it overheated which could be the cause of the problem. But now i'm completely stumped. Any suggestions on how to fix this problem would be appreciated.

Thank you very much for the welcome to seven forums but unfortunately its impossible to check if the drivers are up to date or install new ones because i cannot use my mouse and keyboard to select anything. Ive done some googling and some people suggest that it could be a hardware defect such as a defect in the motherboard, do you think that its probably the problem?

adambee said:

Thank you very much for the welcome to seven forums but unfortunately its impossible to check if the drivers are up to date or install new ones because i cannot use my mouse and keyboard to select anything. Ive done some googling and some people suggest that it could be a hardware defect such as a defect in the motherboard, do you think that its probably the problem?

Get a PS/2 keyboard and mouse. You can access your computer that way.

What do you mean when something was broken on the board?