Turning on Defense + Prevents Vista from Starting

I have a fresh install of Vista Home Premium. Here’s my system info:

Comodo Pro Firewall 3.0.14.276 X32
Vista Home Premium 32 bit
UAC deactivated, user account is an administrator
AVG Free 7.5.516
Asus A8N-SLI Premium MB
AMD Athlon 64 X2 4400 CPU
2 gig DDR
Nvidia 8800 GTS, forceware 169.25
broadband cable
all three levels of Windows firewall off

I installed Comodo without defense +. Everything runs great. If I uncheck the “deactivate defense+ permanently” and put the slider to “training” or “clean PC” the program appears to run fine.

The problem occurs upon reboot. My system goes to the welcome screen then the screen goes blank with only an arrow. Waiting doesn’t help. Eventually the screen saver kicks in but if I bump the mouse all I get is a black screen with an arrow. I can move the arrow but right and left clicks do nothing. I can ctrl-alt-del and get task manager. I don’t see “explorer.exe” in the task list nor can I run it manually. All attempts to run programs from a run dialog are met with system warnings (I forget what they say, but I think its some kind of warning that the file can’t be found or I don’t have the correct permission to run them).

If I reboot to safe mode I can access Comodo and move the slider to “disable” Defense +. Upon reboot my system runs fine. I don’t see anything obvious in my event viewer. What additional info do you need? What else can I try?

Thanks,
Regkaz

Comodo Pro Firewall 3.0.14.276 X32