O thats true =/ cant just use the Windows 7 disc and reinstall it? got the code I did that on my Labtop when i swithed it from 32bit vista to 64bit Windows 7.
If it is not the RETAIL versio, but only the OEM, than u need a new one for $100.
OEM is cheaper, because it can be used only on 1 PC.
Retail is more expensive, because it could be installed again on another PC, if u decide to build a new one, where u will change all the major components, like motherboard and CPU.
The OEM doesn't allow those changes. So if u build PC and upgrade often(every 12 mo.) than u will benefit from retail licence. And u will also get support from Microsoft.
OEM gets no support. Who cares, right : )
So get Windows 7 Home Premium SP1 64-bit ~ $99.99
As a student, u can get even better deal, check http://www.microsoftstore.com/store/msstore/cat/categoryid.37826100/