Hi Digital-flex,
Welcome to Vista Forums.
You might try running a
sfc /scannow command to see if it can find and fix any system files that may be causing this. This tutorial will show you how to if needed.
System Files - SFC Command
If that does not work for you, then you can do a Repair install. This tutorial will show you how to if needed.
Repair Install For Vista
Hope this helps,
Shawn