Windows 7 Pro won't load

Hey guys, ok here is the scoop.
I bought a computer from my bro in law. it has windows 7 pro on it but it wont load. it loads up and says start normally or run repair. I selected run repair and it said windows is loading files... with a progress bar. I let it go to 100% and left it on that screen in case it was doing something for 24hrs and nothing. I do not have the windows 7 pro copy of his because he store bought it and was not parting with it. I have my store bought windows vista disc so I inserted it and proceeded to boot from the disc. it started and said windows is loading files... with the progress bar and did the same as the windows on the HD. so I can not even access the windows disc menu to format or reinstall or anything. any ideas with what I should try? I tried googling it with no results, I am at day 3 of f'n around with it and I am clueless apparently on new tech
 
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