Open up "DEBUG" in a DOS prompt, and write a few-line assembly loop that writes increasing register numbers to port 70h (register select), and 0 to port 71h (value) -- to reset CMOS memory with all 0's.
Then you can just enter BIOS to set it all up from scratch.
I've personally seen a BIOS implementation (on an HP computer, I think) that would let you in if you typed in an incorrect password three times. That was pretty hilarious, maybe the programmers thought that nobody would be that tenacious?
"Fortunately", back in the days when I was at school, the BIOS tended to have backdoor passwords that were easily googleable. That stopped working eventually, but then I happened to procure for myself a second-hand school computer which turned out to have the BIOS password still set when I bought it. Short work to then run a tool to read the password directly from CMOS.
I've forgotten what it was, but for all I know they're still using the same password. Oh, the lengths I went to to run linux livecds...
Funny that you did it this way - I just wrote a single byte using 'o' directly from the prompt, which was enough to ruin the checksum and cause the bios to reset to defaults.
Open up "DEBUG" in a DOS prompt, and write a few-line assembly loop that writes increasing register numbers to port 70h (register select), and 0 to port 71h (value) -- to reset CMOS memory with all 0's.
Then you can just enter BIOS to set it all up from scratch.