Various types or viruses lurk around the start menu. Some even disable you from functioning the links at these menus. Clicking on My Computer might not open and so forth.
A tool checks the registry and deletes various virus files associated from the registry as well as the locations. Hooking them up with CCleaner can help knowing their start up states.
Three cheers to the Malwarebytes' Anti-Malware. Download at: http://www.download.com/Malwarebytes-Anti-Malware/3000-8022_4-10804572.html

Just update and run. It'll find the infected dlls via registry. Good for viruses related to the start menu.
I just had one today where, i could not rename a file.