So I just bought Windows 7 Upgrade and there are 3 parts to the Windows 7 download. I downloaded Win7-HP-Retail-en-us-x64 which I think is an install file. But every time I try to run it I get the error message, "The application cannot find one of its required files, possibly because it was unable to create it in the folder. Please make sure that the folder in which this application was downloaded is accessible and not read-only". I threw it onto my desktop, unblocked it from properties, but still it doesn't work. What do I do?