Windows Installer Problems

My Windows Installer (.msi file extension installer) does not work. It keeps telling me, "This Installation package could not be verified..." and it goes on. Well I had this error on Vista so I decided to reformat since I cannot install iTunes, Quicktime, game demos, and essential drivers and programs. I have tried replacing the files, unregistering and re-registering them. I ran through the services and made sure it was starting automatically and it was on. I tried using the net start command to get it working and there is still no progress. I did 2 full reformats where I spent hours waiting for my hard drive to turn every bit back to zero and for windows to take its 10 minutes to install. I even set my bios to stock settings because I was previously running an overclock. My memory has been tested and my drive too, and there is not a single error present. I can only think to go find my old 160GB SATA drive and try to install Windows 7 on it. Any ideas anyone? I may just move to a custom build of slaxware linux until I find a suitable solution.