[Synthx]

Have you read this page on the HP website? It may be of use but companies never really give a solid answer to anything.

Never saw that page, but I already pretty much know the problem. As stated below, it could be the battery. I really do believe it is the battery being dead because the laptop has been sitting around for almost 10 years now.

Just googled it, and found this:

0251: System CMOS checksum bad. Always power-cycle your system when you receive this message. If the system repeats the error message, follow the corrective action for the error message. CMOS checksum is bad, possibly because the system was reset during BIOS boot or because of a dead RTC battery.