For the last few days I have been able to boot the computer up and when it
comes time to logon, I get:
Log on to windows : winlogon.exe - Application Error
the instruction at "0x75978dc1" referrence memory at "0x00000000".
click OK to terminate the program
click CANCEL to debug the program

Regardless of what I click, it restarts the computer.

I have run a variety of virus checks from different vendors and all state
that there is no virus. I have also checked for spyware with no stated
problems. I deleted the original admin and now have a different admin. I
have tried to restore prior to this problem and it doesn't help. I can use
the computer and all its functions if I don't click on error screen. Any
help would be appreciated. If I do a system restore with the windows disk,
what exactly will happen to all that I have on the hard disk? I am running
the following system:

abit motherboard an8 ultra
1 gig ram (2 x 512) crucial
geoforce 6800 gs pci e video
raid 0 with 2 diamond max 10 200 gig hd
amd x2 3800
2 dvd rw
windows xp home with sp2