Need help to set the CMOS checksum error

Everyday when I start my system I get cmos checksum error and the date and time would be set ot Jan 1st 2000 12.58am. I need to set once a day. Can someone please tell how I can solve my problem permanently? I have windows98 and w2k on my system. Can this problem occur due to not seting the date and time properly while installing windows 2000 os on windows 98 system?