Windows 7 "The Windows Installer Service could not be accessed"

[Chaurigol]

Windows 7 Ultimate x64
Windows Installer 5.0.7600.16385

Screenshot of the error message

Hello everyone, I just joined this community in desperate need for a solution. I recently started receiving this error message whenever I try to install a *.msi program. I have tried every single fix I've found on the net with no luck, these include:

- Unregistering/registering msiexec (in normal and safe mode)
- Exporting [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\msiserver] registry value from a working OS and import it in mine.
- Copying MSI files (such as msiexec.exe, msi.dll, msisip.dll and others) from other Windows 7 OS and replacing them with mine.
- System restore to a previous point.

And many others I don't remember right now.

Unfortunately there's no Windows Installer 5.0 available to download and try reinstallation.

Reinstalling the OS isn't really an alternative right now.

I uploaded my [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\msiserver] key in case someone wishes to analyze it:

http://www.megaupload.com/?d=UZ1RSGW4

I would greatly appreciate any other suggestion.

Thanks in advance!

P.S.: Any additional information you need just ask for it, I will provide it as soon as possible.

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