I had the problem with Windows Explorer crashing, or exhibiting strange behavior on right clicking. System is Windows 7 Ultimate, with 4 Gb memory, E6750.
Using Shell Ex View from nirsoft.net, I disabled Spybot2.0.6 B4 from context, along with Commodo Firewall (firewall only). I have since enabled Commodo. Spybot is scanning, and Explorer does not crash, but the scan slows down program startup a lot.