Yesterday I swapped out my old-ish AMD cpu and motherboard for my brand new Intel ones but I completely forgot to sysprep Windows 7 or back up any files and obviously W7 can't boot. I have the USB that I originally installed W7 on my computer. Would I be able to use the USB to repair the OS or reinstall it then just pop in the mobo's disk without losing data? Or will everything get wiped?

It's not the end of the world if my HDD gets wiped, just as long as I can get my computer working again without having to spend more money on anything. It'd just be annoying.

To be safe, you may want to make a Linux Live CD on another computer so you can backup your data.

When I reinstalled Windows 7, it just tossed everything in a folder for me and then installed over the rest of the stuff. So, I had the folder from the previous install. This was with the retail disc, by the way. I was a bit surprised it did that, personally.