Sony Vegas Uninstall Assistance

I recently tried to run an installation of sony vegas 9.0 on my computer only to find that it had become corrupted. I went to try and uninstall it via the windows add/remove programs dialog, and it popped up with a dialog box asking for a file called “moviestudiope09_enu.msi”. I located that file and pointed the windows uninstaller to it, however it says that it is not a valid installation package. I tried three other versions of this same file, and nothing worked.
Since that did not work I tried removing the files manually and then removing all associated registry keys. It still remains in the add/remove programs list and when I try to re-install the program, it says that I have a newer version of Sony Vegas installed, and to uninstall that one before continuing. I also tried using ccleaner and Revo uninstaller to no avail. I cannot get a working copy installed without uninstalling my old one, and I have not found a way to uninstall it thus far. If anyone can offer any insights, it would be much appreaciated.

EDIT:
OS: Windows 7 Home Premium 32-bit

EDIT (again): Someone pointed me in the direction of a few hidden registry keys that didn’t use the same naming convention as the rest of them. After I deleted those, I was able to install a working version again. Thanks anyways guys.

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