that that complex piece of machinery called a PC relies on a little battery to keep the clock working? It's on the motherboard and is flat and silver, like a large hearing aid battery. Replace it.
Since you didn't share the make and model of the PC I'll let you investigate/read the owner's manual for the procedure.
Hi everyboby me being a bit PC dull maybe asking a silly question ,, I upgraded my PC from XP Pro to Vista Ultimate since doing this my PC clock will not keep the correct time ,, if I shut down and restart the clock displays a different time if I adjust it on the time a date it will still not keep time and the apply tab does not function just the OK ,,If I sync with the internet time same applies the clock will stay correct as with the date and time adjustment until it goes into stand by when I restart the time displayed could be anything so I have to adjust the date/time again that's the gist of it folks anyone know a fix thanks for reading best regards to all ,,,, Tony