ms licensing

I have an windows 7 ultimate upgrade disc that I bought at the university while I was studying there. I used it on my computer years ago.

The question: My brother has a new computer for his business that is Windows 8 and he wants windows 7 on it. Could I use my upgrade disc for a second time? Will it pass validation?

EDIT 1. I know technically it is a "student" disc, so it crosses the line there a bit. And honestly, I used it on the first computer as a clean install (simply installed it twice from the $30 upgrade disc and got a brand new version of 7 ultimate).

But I don't want to 7 and not have it pass validation, because then I won't be able to revert back to 8 (especially if I do a clean install).

EDIT 2. It's just always unclear to me. I have a student copy of office pro 2007 and have used it for countless people. They don't seem to care.... or do they...?

Jam it back in, in the dark.

There is a certain amount of times you can activate a Microsoft product online before they'll stop allowing new activations using that key. The amount of times varies from product to product and version to version. Once you reach that limit, you have to call them to activate. Most times this isn't a problem if you can give them a good enough reason why you're installing a new copy of Windows, but there is a chance they'll deny you activation.

There's nowhere I can't reach.