Bios password ibm thinkpad g40
Sounds like you tried this, but it's worth a shot again. Remove the CMOS battery on the motherboard and let the laptop sit for an hour, then replace the battery with a new one.
If the only real issue is changing the time and date, you can do this in Windows and it will reset the BIOS clock, too, of course.
If the problem is that the time and date keep reseting, you either have a low CMOS battery or a short on the motherboard that is resetting it.
If all else fails, you might need to flash the BIOS from a floppy disk with the latest BIOS version for your machine to reset it and go from there.
PS: BIOS reset problems on laptops are sometimes due to power problems caused by battery packs going bad; check your battery pack, too, and see if it is working okay.