TIP: IBM Thinkpad 192 error 2 bleep, test screen.

I have a thinkpad 600e laptop and a few days ago on booting up I got an unexpected 192 error, two bleeps and booted into IBM Test screen. Gives options to test or reboot. If you press test, there are the following errors on the systemboard:
DEV 001
ERR 91
Fru 3610

Which is basically IBM speak for 'What the??' Don't panic and think it has to be the systemboard. It's probably the cmos battery needing replaced. This is a backup battery which keeps the system clock in time. Yes, an out of time clock on your desktop can mean you have a virus, so it's worth doing a through scan, but in most cases it's a dying cmos battery. They should be 3 volts, so if you test your existing battery with a volt meter and it's low, better get a new one. New batteries are very cheap and in fact if you have the ability any lithium battery CR2025 should work in a 600e - a guide to how to fit these are on the web, but there's a good discussion of www.stonetable.org.

If you can on boot up press F1 which should take you to the bios screen to check/adjust the internal date/clock, but it probably won't work with the 192 error, but once you've fitted a new battery do this and make sure the time/date is correct. Nevertheless, as my battery was not totally dead, I could force the IBM to boot into windows from the IBM Test screen by pressing 'reboot' and then pressing F1. Don't know why, but the laptop would then go into scan disk mode, perform a scan then boot up. I have to adjust the clock time, but once booted, the system works fine, with no errors. Odd, but okay while I'm waiting for a new battery to arrive.