Keyboard & Mouse Not Working

I took my computer out to clean it and air the dust out of it with an air-can the other day, and I went to plug everything back in and everything is working fine besides the keyboard & mouse, and seemingly everything that uses the USB port. I'd think that the USB ports are fried, but this is the strange part. I am able to use the keyboard to enter the BIOS screen, and when Windows XP is booting up, about mid-way on the boot splash screen, the light on the keyboard turns off and everything stops working. What is causing this? I think I've tried everything, restoring factory defaults on BIOS, trying completely new mouses and keyboards, etc. Please help.

Thanks,
r.hall

Do you have a PS/2 keyboard or mouse you could try out?

Also, is it possible you knocked something loose inside the case when you were spraying around?

What ports are you using for the USB components? Front ports, back ports that go into the motherboard? Or is it a PCI USB device?