I'd guess that it is much more likely to be caused by installing too many applications that hook into Explorer and the Shell.
and have a look at what has been installed into your shell - I bet you will be surprised at the amount of stuff that appears there. If there is anything you find that you no longer use try uninstalling it from Control Panel > Add/Remove Programs.
You can use ShellEx to temporarily disable most of these things. It all looks very complicated but it is pretty easy to just disable everything and then re-enable stuff a bit a time.
I'd suggest you do that (ie. disable everything in ShellEx) and see if your problem is solved by opening My Documents - if it is you can re-enable extensions a few at a time and see when the problem reappears and so track down what is causing the problem. Just leave ShellEx open on screen and cloase all Explorer windows - enable a few items and then open My Documents and right click somewhere in the window - if it opens quickly and the menu pops up quickly you can be pretty sure everything is working so far, if not disable the things you just enabled and enable them again a couple at atime and check My Documents again.
It isn't always that simple - sometimes extension interfere with each other and you need to be a bit of a detective to work out which one is actually causing the problem.
If you establish which one is causing the problem see if you can figure out which application would have installed it and then uninstall that applicationa dn reinstall it - hopefully if something was corrupted it will be cured. If two apps are interefering with each other it can be more difficult and you may need to decide if you can live without one of them!
If you try this out and need some help post a screen shot.
Can I suggest you start a new thread as this is just a bit off topic!!!