Microsoft Visual Studio The operation could not be completed

Here is my problem with Microsoft Visual Studio.
I have been getting this error message from past a few days and hope some expert here would help me with this.
I have Microsoft Visual Studio 2008 installed on my Windows 7 Pro machine. Initially all the options used to work fine.
But now when I try to do a search or try to go to some help directories I get an error message that there is no interface found.
I am sure it was working before.
Please help.
Microsoft Visual Studio
The operation could not be completed. No such interface supported.
