CMOS keeps resetting

Well, had a power brownout. WinXP Home edition install was screwed. So I reinstalled completely. The problem I'm having is that when my system is after my system is powered up from a completely powered down state, I get a error message stating my CMOS is not set up. I've set up - time, date, and a couple of other settings- a couple of times now. Everytime I power down the system, the info is lost. On a soft reboot however, the CMOS keeps the info.

I've already replaced the CMOS battery with a duplicate of what was in there. Problem persists. Is it possible that the actual CMOS was damaged? If so, is there a way to replace it or am I screwed into either never powering down or buying a new motherboard.

P4 3.0Ghz
Asus P4C 800 Deluxe Motherboard
1024 Corsair RAM DDR 400

Any help would be appreciated.