Posted 23 February 2010 - 03:31 AM
I think you will probably need to temporarily connect whichever alternative keyboard (PS/2 or AT) the system has input for, enter the BIOS setup as indicated on the boot screen, and enable an option which is commonly called Legacy USB. The system should then respond to the USB keyboard prior to Windows starting.
This often occurs on older systems when the CMOS data has been reset back to BIOS default values. Make sure the CMOS backup battery hasn't gone flat, or it is likely to happen again.
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