The problem was reported by one of our readers who was troubled by the error message that comes up every time he opens Control Panel and reading

“Windows cannot find C:\Windows\Rundll32.exe make sure you typed the name correctly and try again”.

Cause of the problem:

The problem is caused only due to the damaged or missing Rundll32.exe file from the Windows directory.

Steps to fix the problem:

1.    You just need to provide a new file called Rundll32.ex_

If you have XP CD:

•    Load the CD into the drive and open the Run box

•    Type the command expand  X:\i386\rundll32.ex_ c:\windows\system32\rundll32.exe where X is the letter of your CD ROM Drive.

If you don’t have XP CD:

•    Then download the rundll32 file and type save it into the C: drive after unzipping it.

•    Type the command in the Run box expand  C:\rundll32.ex_ C:\windows\system32\rundll32.exe

2.    Reboot is required.

[Via MS]