RE: ShellMenuView. That really is odd. There should have been some entries listed at least. Example:

I have to ask a question. After doing some research I see that a few users have reported the same problem. One of those states that the problem occurs only when Explorer window is maximised. Perhaps you could try resizing the window to see if it makes any difference. I'm not sure that it will but who knows?
On another note how many user accounts are set up and do you have access to the built in administrator account?
Try this:
Start> Run then type
netplwiz
Press Enter.
What do you see listed? Or post a screenshot.
If other accounts are available try logging in as a different user or try logging into the built in administrator account and see if the same problem exists there.
See tutorial here:
Built-in Administrator Account - Enable or Disable
Note
It is best to disable the built in administrator account and enable only on a when needed basis.
RE: Your question on permissions. That's not something I have much experience with but presumably you have not been changing permissions on anything right?
I have reset permissions on my own machine in the past.
[EDIT]
Another thought. How have you got folder view options set? Try setting them like this:

Also on the general tab set to "open in same window"
Computer > Organize> Folder Options> View.