What JBI said. Also, if you're having problems with your media, Microsoft does make the media for all versions of Windows Vista and 7 freely downloadable via DigitalRiver links. If you've got a good serial, that's all the rest you'd need. If it's an OEM machine, that came with Windows 7 preinstalled, you may have a restore partition you can make use of, as well.
pa' ngaSwI' nuq vay' Data'nISbogh roD tu'lu' tlhIH'a'?! yIn jaj tera' na'ran wIb laH HInob Qub 'oH rue munISbogh 'Iv ghaH DaSov'a'? loD chay'pen tuqwIj meQ 'Iv jIH! TERA' NA'RAN WIB! chay'pen burns tuq vI'ogh 'ogh, chombuStIble tera' na'ran wIb!