If I uninstall my 64 bit version of windows 7 can I reinstall the 32 bit version and use the same license key?

Yes you can.

Since the release of windows vista, microsoft have been using a universal key for 32 and 64bit versions of windows.

So both 32bit and 64bit have the exact same keys.

so again, yes you can use it.

(im not sure why you would want to. There is only a small few pieces of software that wont work with 64bit os, and those are ones containing 16bit code, meaning from like win98/ME days.... as 99% of 32bit software works fine on 64bit, so you probably just did something wrong >.>)

Go to google and kind in firefox 32 bit down load and click on the first hyperlink then down load it there isnt a flash player for 64 bit yet that you may also use the 32 bit variation of internet explorer just click on on the home windows icon and typc internet explorer within the "search applications and features" area

NO