Hi,
I would suggest you to run SFC. The sfc /scannow command scans all protected system files and replaces incorrect versions with correct Microsoft versions. When the scan is complete, the System File Checker tool indicates whether integrity violations were found. If integrity violations are found, the System File Checker tool lets you fix the integrity violations. Refer to the following article to know how to do this.
Use the System File Checker tool to repair missing or corrupted system files
http://support.microsoft.com/kb/929833
Hope this helps.