Hi
One step you can take to try to fix this problem is to run the system file checker. Click Start>Run and type:
sfc
in the box, then click OK.
When sfc starts you have two options. You can check all your system files to make sure that you are using the latest version of each. If a version conflict is present the program will display the currently used version beside the previously used version - check the version numbers and make sure you choose the highest version as the one to use (sometimes an earlier version will be used in preference to a later one if a program has been installed that has copied earlier versions of files which have a later timestamp).
The second option is to extract a file from the .cab files. Simply type rundll32.exe in the File to extract field and click OK. If you are still experiencing problems after this, you should get your system examined by anti-virus software.
Good luck