Windows Installer: Error 1721

I tried to uninstall a program called NetDisk from my Win XP, and for unknown reasons it hung during the uninstall. Now every time I boot or try to download anything or in numerous other occasions I get the Win Installer popping up to try to finish the uninstall. About halfway through it stops, and Win Installer gives the "Error 1721" dialog box. I've tried MS's fix with sfc purgecache, two different registry editors, checkdisk and even (against my better judgment) deleted a few registry files with the name NetDisk in them. So far, nothing has worked. It's the pop-up from Hell, and it won't die!

 

Are you certain that it is NetDisk that is invoking the Windows Installer? If so, you can use the Windows Installer Cleanup utility to remove it.

http://support.microsoft.com/kb/290301

Install it, then run it from your start menu. Then you can choose the offending application from the list and remove it that way.

 

Yes, it is definitely NetDisk uninstall that comes up first, then Win Installer's message.I forgot to include that I have already tried the the Cleanup Utility. Unfortunately , I deleted all the NetDisk files thinking this would solve the problem. Thus, it doesn't show up as a Program on the machine, so the Cleanup doesn't show anything to delete.

 

It might be worth it to use System Restore to the point prior to you removing the registry entries, then using the utility.