One irritating message that greet you when you switch on your system one fine morning will be “Enter Time and Date”. This will come repeatedly till you replace your weak battery. It is very easy and may be the first step you can try on your mother board. I will put it in step by step way.
1. Switch off and isolate the main supply.
2. Open the cabinet cover so that your mother board is visible.
3. Look around and find the system battery on the mother board.
4. Remove the weak battery located on the motherboard.
5. Replace the old battery with a new battery.
6. Put back the cabinet cover.
7. Connect and switch on the computer.
8. Now you have solved a nagging problem!