+ 0 Votes Sounds like bad MOBO robo_dev 5 years ago Sounds like a new MOBO may be needed. Since the hard drive failed, sounds like a power surge got sent thru the whole PC and the 5Volt side of things on the motherboard lost a component or two. After defaulting the BIOS, a USB keyboard should work just fine, so that is not a good sign. I'm sure you tried more than one USB port. When the keyboard stops working, I assume that the caps-lock light goes out and/or stops responding to capslock switch? From a technical standpoint, either it's not getting voltage, clock, or data, but that's not really relevant unless you're planning to do some component-level repair on the MOBO. Pin 1 KBDAT (data) Pin 2 not used Pin 3 GND Pin 4 VCC (+5V) Pin 5 KBDCLK (clock) Pin 6 not used + 0 Votes Your Welcome < NT > OH Smeg 5 years ago .