WindowsExplorer top left, File&Edit options are not working!

You may have "context" and "menu" problems - have you fix the "view source" problem as well? - also have you removed any spyware or viruses lately?

Here's a bit of heavy reading if you are that way include which explains "how it all works" (ie the Identity and directory service")
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/mmc/mmc/working_with_context_menus.asp

First thing to consider is a restore point?

Next try this:-

From the Start menu, select Run.
In the Open field, type sfc /scannow (Note: There is a space between sfc and /scannow)
Select the OK button.
Follow the prompts throughout the System File Checker process.
Reboot the computer when System File Checker completes.

Let us know how you go.
Peter