Can anyone give me a clue as to why i am having to change the battery in my pc approximately every 3 to 4 weeks. First it loses the time then when i switch on it says cmos settings are wrong, i install a new battery & everything is ok for another 3 to 4 weeks then the same thing happens over again! Any help would be welcome.
Thank you.

Have you tried clearing the cmos? Near the battery should be a jumper block labeled cmos. Usually 3 pins with a jumper shorting 2. Unplug from electric outlet: remove battery: then change the jumper from present setting (usually 2&3) to 1&2: let set for a few minuets. Then re-set jumper: replace battery: plug-in: boot.

Hi, yes ive already tried that ,it makes no diferrence at all.

A short on the FLASH will do it as well as a bad connection on the MB. Your battery is intended to maintain a small amount of energy to the RTC and some CMOS configs. Most CMOS/BIOS is now on FLASH which requires no battery. If you have a board with a bad power regulator that trys to recharge the battery (we are talking really old here) or there is a slight cross connect on modern boards it will cause the bat to discharge into the main board to keep the 5v signal. The latter is a really big defect and would have been noticed by you right after you bought the machine.

Thanks for the info, I guess it must be a bad connection ,as the board isn't that old, PC333 ddr m851 series.

BTW, My wife works witha compac presario that has the same issue as what you are describing. I removed the battery socket and had her just update the time when she reboots. This has worked fine for her, but I do not recomend it for just anyone. I actually had my meters on the board the find the problem and was able to isolate it to that...so its something to think about.