Windows Installer Service could not be accessed

I have a user who is using Windows XP X64 and his windows installer will not work properly. He is not able to uninstall any application. I have found a kb that asked me to start > Run > msiexec.exe /unregister than msiexec /regserver than reboot. This does not resolve his issue. He is receiving an error that the windows installer could not be accessed. I checked the reg permissions and they all seem to be fine, system has full control over H_K_C_R.

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JohnBusiness Consultant (Owner)Commented:
Have you tried updating and/or reinstaller Windows Installer? It changes (updates) from time to time. Go to the Downloads section at and see if you can find a new X64 XP version. That is what I would try first.

Also, have you scanned for malware as this is anohter cause of this.  ... Thinkpads_User
cheesebugahAuthor Commented:
No, I have not ran a malware scan, did not think of that. I did run a sfc / scannow with the xp x64 dvd... I will try to reinstall the installer service and see what happens.
cheesebugahAuthor Commented:
We did run a system restore to a previous date ( this past Friday ) and all is well. Thanks..

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