the 32bit will be no problem. 32bit Win 7 will run on a computer with a 64bit architecture. The other way around does not work.
end result--Null Problemo.
Which did you buy? OEM (system builder), Upgrade or Full?
Best Buy has been known to unknowingly sell counterfeit versions of Win 7, but that is unusual.
Did your DVD come with a 25-character Product Key? Yes/No?
Do not post the key. That's what you paid for and which is yours alone.