Breakpoint

I have been getting an error message lately on bootup:
The Exception Breakpoint
A breakpoint has been reached 0x80000003 occurred in the application at location 0x7c839a95
This has occurred citing 3 different applications - video driver, printer driver and one other, so that I don’t think that it is really the applications cited that are responsible. Google shows a few (very few) hits that generally mention Zone Alarm. The alert is dismissable without reboot.
Comodo v.2.4.18.184
O/S WinXP MCE sp2
Login as Admin
Security: Spyware Doctor; BOClean; CPF
This may be related to Spyware Doctor, but the mention of Zone Alarm in Google made me wonder about CPF. Ideas???

Have you ever had Zone Alarm installed on that computer?

No - I went from the Windows firewall to Comodo because it had great reviews. Not too surprising, really. BTW - forgot to describe the system:
AMD Athlon 64 X2 Dual Core 3800+
ATI 2006 Wonder video card
1 Gb ram
Wireless LAN via USB dongles and a wireless router

Check Event Viewer for clues. The system logs both error and normal operational logs. Errors are prefixed with either a white X inside a red circle, or a yellow warning triangle. To open Event Viewer, run eventvwr.msc and then examine the logs in both the Application and System submenus. If there’s a link to Microsoft, click that to get more info.