I'm having essentially the same problem..... you might try running ShellExView to locate any faulty handlers. It could be due to a bad context menu handler, like a 32bit handler conflicting somehow. It didn't solve my problem but it might solve yours Look for non-M$ handlers first.
Thanks for the information. Not a big deal, just a bit annoying sometimes. Another question I have is if anyone else has problems with their mouse settings. Basically 90% of the time I click my mouse once and Windows takes it as a double click and I end up opening programs that I don't want to open. It's also a pain when I'm signing up for something and I try to tick a box, because since it's double clicking even though I click once, it's getting rid of my check box. Just really annoying lately. This didn't happen with XP. But perhaps it could be my mouse.