Messed up Registry, even broken registry
Try system restore or do you use ERUNT to backup your registry ?
if failed, try 'Last Known Good Configuration' at booting.
I suggest, throw out RegCure, Registry Patrol and AdvancedRegistryOptimizer ( i'm sure this is caused by them).
Keep CCleaner and replace Spyware Doctor to SuperAntispyware.
the rest, its up to you.