Hi,
- Were there any changes made on the computer prior to the issue?
- Which operating system is installed on the computer?
- When exactly do you get the error message?
- What are you trying to connect?
I would suggest you to refer to the link to use the system file checker tool (sfc) to troubleshoot missing or corrupted system files in Windows:
How to use the System File Checker tool to troubleshoot missing or corrupted system files on Windows Vista or on Windows 7
http://support.microsoft.com/kb/929833
If the issue is not resolved, please provide more information to assist you better.