Hi
You can try this...
Open the command prompt as administrator.
Type...
SFC /scannow
and hit enter.
It will scan all your system files looking for errors and repair them if it can.
I really don't see other people reporting this problem so it's not something common.
If worse comes to worse you may have to do a repair install, but start with the scan.
Anyone else have any ideas?
How to repair Windows 7...
http://www.sevenforums.com/tutorials/3413-repair-install.html
If you decide to do this back up your data first, this process should leave it all intact, but better safe then sorry.
Mike