What do i do if my PC can't remember the time of day or current date?

The battery on your motherboard that powers your CMOS chip has died. This happens after three to five years. You will need to turn off your PC, open the case, and look for a small lithium battery on the motherboard. It’s usually easy to find, but your computer manual may point you directly to it. Remove the battery and take it to the store, where you need to find a replacement. Pop the new one in your PC and close it up -- You are done.Unfortunately, you will have lost all of your CMOS settings, so its good idea to keep a written record of all the CMOS data before disaster strikes. Some utility programs (Such as Norton utilizes) also save your CMOS settings to disk.