As WINDOWS 7 is the newest, and latest O. S. product from good ole Microsoft, in upcoming weeks and months, lots of people; professional Techs, and regular Users are going to be faced with thousands upon thousands of new obstacles and miscues. Purchasing the 32bit version of WINDOWS 7---or a combo pack of 32/64---is currently the easiest and safest way to go! Still few manufacturers offer their Hardware with Software support for 64bit. Of course, most likely this will be the next wave of the future, but for now, most PCs are operating 32bit Motherboards, components and such.
Performing a CLEAN INSTALL vs an UPGRADE is a matter of decisive choice. Though, if you've been having problems with your current Operating System and PC, then chances are, an UPGRADE type of Install is not going to fix your problems. Of course, a CLEAN INSTALL guarantees you will most likely lose previous info and data, but if you back that data up onto a separate Hard Drive, you will be able to retrieve it later (if you don't have two or more Hard Drives installed in your PC, then a stand-a-lone USB type of Hard Drive can be purchased for under a Hundred dollars ($100).
With most of the 32bit Microsoft Windows Operating Systems, technically knowledgeable advanced Users, or Techs while paying exclusive attention during an Install, can direct the Operating System Setup to install without overwriting existing data, however this procedure and process requires a lucid working awareness and understanding on manipulation and navigation of existing Hard Drives.