Did you save your settings? Whenever you boot a computer, the system scans your hardware to see that it matches what is saved in the CMOS. The process of replacing the battery resets the CMOS to the factory defaults - which has no clue what drives, CPU, or RAM you have installed. So whenever you reset the CMOS, you need to boot into the BIOS Setup Menu, verify your drives are correctly identified, and set/verify the Date and Time. Then you must Save and Exit. If you don't save, next time you boot, the system will find the defaults don't match your hardware again.

reinstall a fresh copy of window