Hi Al
How old roughly is your PC?
If that is 3 years or more, most likely the CMOS battery (looks like a watch battery) on your motherboard needs to be replaced . . .
If your system is not that old, check the support page for your PC on the manufacturers website, to see if there is a BIOS update available for your PC
If you have any difficulty locating that support page, what is the Make and exact Model No. of your PC - that will be printed on a sticker on the bottom casing . . .