Win 7 32 bit vs 64 bit--installation

Win 7/32 is currently my operating system.My computer is 64 bit capable and I am contemplating an upgrade to 64 bit.Should this be a clean install? Is there a good source to guide me through the process?
GAP

GAP, Welcome to the forum! Yes, it should be a clean or "custom" install, as the install disc calls it. You need to backup anything you don't want to lose first, then proceed with the install. It's really simple, you just boot from the disc, there will be a notice to press any key to boot from DVD, and you choose which partition you want to place it on, be sure to format it, and it will run unattended for a while, then you'll need to key in your options and COA key #. What version of Windows 7 do you have? You can download the 64 bit version of the same version that you have (Home Premium and Pro) and use the same key to install it with, or if you know someone with the disc, you can use that. Post back and let me know what version of Windows 7 you have, and I'll let you know which disc you need, P.S. This is a legal disc, not a pirated one.

Go to the link below and follow the info to get either Home Premium or Professional.

Windows 7 ISO – Official Direct Download Links