After getting a BSOD, I turned off and repowered my Dell Dimension. It got to the login screen, at which point the USB keyboard and mouse stopped working. I repowered and found that my keyboad still worked prior to reaching the login screen. I made sure that UBB devices were enabled in Setup, but still nothing. I've tried all USB ports (front and back) with now luck. The light on my mouse will flash for a second when I plug it into a port but then goes out. I've checked both the keyboard and mouse on another computer, and they both work fine.