Win 7 will run anything except a 16-bit program (which means it is really ancient).
No, you can't just "uninstall" windows. Gotta wipe the drive to do that and then reinstall your "new/old" operating system.
Also, you can't just save your current configuration to disk(s).
You'll need an imaging software to take a "picture" of the hard drive and place that image on an external drive via USB. I'd recommed the Macrium Reflect from macrium dot com. Use the free one as the one they sell is a total POS.
The free one really works nice!