A virus scanner removed the MS Windows rundll32.exe file. The system still booted and would run, with many annoyances.
How to replace MS Windows \WINDOWS\system32\rundll32.exe
Error message identifying missing file:
File is missing:
Open a command prompt and run System File Checker.
Start Button --> Run --> cmd
At command prompt type: sfc /scannow
With the installation CD in the CD drive, expand the file from CD to the MS Windows installation.
File rundll32.exe has been restored, with a current time stamp.
While not necessary, set the file attributes to read only.