Corrupt Permission Settings in Windows Vista

[stantough]

I'm using Windows Vista 32, and I am having the problem of not able to install software that uses Windows Installer. I get the error message saying Windows Installer could not be accessed. I've tried all the solutions on the net including:
1) Downloading registry fixes and running them
2) going into msconfig (Windows Installer is "stopped" and there is nothing I can do to enable / disable / start it)
3) Going into services.msc (I've changed Windows Installer status to manual and tried to "start" but i get error message "access is denied")
4) Trying to find the WOW64 registry key under the Windows Registry and change it to 0 (but beecause I'm using Windows Vista 32 i don't think this is relevant for me)
5) Deleting the ENUM subfolder under the msiservice folder in the registry.
6) Running scannow under Command prompt, with Windows operating System cd inside
7) Even tried "installing Windows VIsta" using the operating system CD, but I get an error message saying cannot create the required installation folder!

None of the above worked for me! I still cannot install anything that requires windows installer.

Please help..

If the following is useful:
A while back I tried playing with the permissions of folders (i.e. right click on C drive, properties > security tab > users) and I terminated the action while it was trying to apply changes in giving / removing permission to various users and got the information that some permission settings may be corrupted. As of now I can't set permission in C:, in system32 etc. Even though I am the administrator and there is no other users in this computer, and I have already disabled UAC. Could this be the cause of the problem? If so how do I resolve it

Thanks in advance.