What is i/o card parity interrupt at f000 b5e6?

I am receiving an error that states that i/o card parity interrupt at f000 b5e6. I am working on a Optiplex 380. There are no cards installed. The bios version is A01. I can’t input anything with the keyboard for the options to (S)hutdown or (R)eboot. I am running XP, with 4 Gb RAM, intel dual core duo.