64 bit OS support huge memory. 32 bit support only 3.5 Gb of memory and you can see in windows 7 - 4 Gb with 32 bit OS but that system use only 3.5 Gb. Yo can not upgrade 32 bit system to 64 bit and reverse. I think that windows 7 DVD come only with one of version system (32 or 64 bit) because I use Windows 7 at work and often install that OS on other PCs with two DVD, one 32 - second 64 bit version. For me the best OS is Windows xp - forever. I use Windows 7 but also have Windows XP - dear to my heart Sorry about my bad english.
Hi, I have DELL laptop i3 processor, 4GB RAM and window 7(64 bit). I'm using this from last one year and I haven't faced any problem related to window7. I would say that I got this suggestion from helppconline (online tech support company). and about OEM, I believe that the OEM version can only be used once and has no tech support from MS. The retail version can be installed on multiple computers (one at a time). This means you can install, then uninstall, then install again on another computer. Thanks