PC help: Short-term memory

Q I have a computer based on an AMD Athlon XP 2800 processor. It has worked well, but recently I have been receiving a CMOS Checksum error when the computer starts. The Bios is set to halt on all errors, so it asks me to press the F1 key to continue.

On pressing this key the system reports that defaults are being loaded and it then appears to start up as usual. The PC then seems to work as normal and all the software works fine, but the date and time have been reset.
Geoff Crowther

A It sounds like the CMOS memory – the part of the PC that remembers all the basic settings – has become corrupted.

This is not usually a serious situation. The first thing to do is to reset the Bios. You will need to open the computer and place a jumper across a pair of pins on the motherboard. If this sounds like a worrying task, contact a reputable computer repairman to do the job.

Otherwise, it’s a case of looking for your motherboard in the manual or on the manufacturer’s website. This will list a way to hard-reset the Bios using a jumper. Do so, then close the PC’s case and restart.

Enter the Bios set-up – press Del, Esc or F2 when starting, depending on the PC – and reset the clock and other values. If that doesn’t work, the battery inside the computer may have run out.

This keeps all the settings current while the computer is off, so if it dies, you will see these types of errors. You can replace the battery easily – it is a round, flat watch-type battery located on the PC’s motherboard.

Remove it and buy a replacement with the same model number from a battery dealer such as a watch repair shop.