Hi David,
1. What were the changes made before the issue occurred?
Step 1: Perform a System File checker scan
http://support.microsoft.com/kb/929833
Step 2: Start the computer in safe mode and check
http://windows.microsoft.com/en-US/windows-vista/Start-your-computer-in-safe-mode
**Step 3:**If you don’t get the c:\windows\system32\netprofm.dll, then perform a clean boot and find out the cause.
How to perform a clean boot: