I got this absolutely frustrating problem today in Windows XP, and it took me more than a few hours to find the cause. Darn Windows !
If you click "Help and Support" (Start > Run > Help & Support) and get "Windows cannot find HELPCTR.EXE" here's a possible solution to your problem.
- Start Regedit, by going Start > Run and typing "regedit" without quotes
- Go to HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\App Paths\HELPCTR.EXE
- If the key doesn't exist, right click and create the key : "HELPCTR.EXE" (sans quotes)
- Ensure the value is C:\WINDOWS\PCHealth\HelpCtr\Binaries\HelpCtr.exe or create this value
- Reboot the machine and try again
Woot! Should be fixed! Yay!