The clock goes to the wrong time after switch off. I then have to reset it on switch on. Is there a CMOS battery inside my desk top processor? If so, what No battery should I buy, and how do I install it please? Please note, this is NOT a lap top.

That was my thoughts. BIOS IS where you set the system time and if doesn't keep then the CMOS battery needs replaced. Same goes with the laptop. Access the BIOS and update the time. Here is a picture of a laptop with the CMOS BATTERY.

probably need to replace cmos battery as it is probably not holding charge therefore not keeping internal clock going ,every time you restart it goes to it original clock setting when made as default time.

Your CMOS battery needs to be changed. When you start the computer you put the information in or it resets to a default value when you disconnect power that clears the CMOS memory as though it had never been turned on before. The CMOS battery is on the motherboard so you will have to open the machine up. It normally looks like a large watch battery a little larger than a nickel and a little thinner.

The MCOS bat is inside the tower.Just screw off the side plate and look for a watch like bat and take it with you to any watch or bat store.Go to http://www.google.com.pr/search?q=cmos+battery&hl=en&client=firefox-a&hs=sC6&rls=org.mozilla:en-US:official&prmd=imvnsr&tbm=isch&tbo=u&source=univ&sa=X&ei=7bZ9TomvGNCSgQfz54lM&ved=0CEMQsAQ&biw=1440&bih=750 to see some samples.

First remove the cover of the cpu remove cmos battery and switch on the computer then switch off and replace the battery it will reset the bios and the clocking will be normal if this doesnt work you will see a conctor near cmos battery with two pin inserted with an jumber remove the jumber conect the jumber to the next pin then restart the computer and switch off the nreplace jumber back to the position in some case the changing of the pin wont start the computer switch off and replace the jumber back to orginal position it will reset the overclocking

Yes it very probably is the CMOS battery, time is kept counting electric pulses, when the computer is turned on there is power and memory to do this, but when it is turned off it relays on the battery to keep this an some other settings, maybe you're receiving a warning at boot time. Check this guide for replacing such batteries:

http://www.computerhope.com/issues/ch000239.htm

it sounds like the cmos batt had the same problem with my desk top once changed cmos batt all was fine .the batt is located on the under side of the laptop you will see some removeable panels just check under these,but be carefull the batt might be soldered in, some are some are not. if soldered in you might want to get a professional to change it as the heat could damage your computer.
hope this helps.

hi,
Coin-shaped batteries on most motherboards should be CR2032. Make sure it is properly installed and + is up. IF you have a multimeter or you have a friend who has a multimeter, remove the battery and check the voltage. It should read 3.0 volts when fully charged. If it reads 1.8 volts or higher is probably OK. Be very careful installing and removing coin-shaped batteries. Most of the battery holders i have seen for these batteries are quite fragile and easily broken. I ease these batteries into the holder with the aid of "tweaker" (small screw driver).

here is a video, you can see how to remove the battery or bypass bios password.

there are a number of things that could be wrong here, firstly reset the cmos on the motherboard, if you cannot find the cmos jumper then remove the battery for 10 minutes (make sure the power cord is removed from the back) press the on/off button a couple of times, this will drain any remaining power from the board and properly reset the cmos, while the battery is out remove the memory, clean the contacts and repace, put the battery back in and connect power, if the machine turns on, job done, if not then it could be something far more serious, check the power suppy if could be faulty, the processor may have blown or the motherboard itself may have blown, the only way to check all the components at once is to get a working motherboard which supports your processor type, the same model would be an advantage

CMOS is a memory chip on your computer that stores BIOS information as well as system clock. It powered by a 3V backup battery. If your computer is more then 3 years old it is possible that the backup battery on your PC needs to be replaced. Replace your battery then go to BIOS setup and adjust your date and time. But it is also possible that the clock is a bit off, so first your can just try to adjust your clock without replacement of the battery. You can also do it inside the windows from control panel. Be sure you have a correct time zone.

Good Luck!