You know the situation. An old PC has sat in the corner quietly getting on with its business for years, until something finally goes wrong and then you can't get into the Basic Input Output System (Bios) because there's a password and you don't know what it is.

In this situation there are several methods you can try before resorting to a large hammer.

First, check to see if there's a Bios reset jumper on the motherboard. If there is, leave the jumper covering the two pins for a few minutes to let the CMOS discharge before powering the machine back on.

If there isn't a jumper or you can't find it, then you can just remove the battery. This method can take a few days to work while the CMOS discharges.

If this is an unacceptable delay, or you can't be bothered to take the case off the system unit, then drastic measures are called for.

One method is to boot into Dos with a boot floppy (always a useful tool to have). Make sure you copy Debug onto the disk. At the command prompt, type in the following:

Debug
o 70 2e
o 71 ff
Q

When you reboot the machine, you should find that the Bios password has been erased.

Be warned: this fix will only work under Dos 6.x and 7.x. There is no guarantee it will wipe the Bios, and we take no responsibility for its use!