New
#21
Whatever you decide keep a current image of Win7 so you have a path back. You can always move your Win8 Upgrade to another PC to restore Win7.
You can also run an in-place Upgrade of Win7 keeping all files and programs in place while changing out the OS.
But even in a Clean Install you can always reinstall your paid software using the Product Key and installer. If you've lost these you can audit all of the installed software and hardware including Keys using Belarc Advisor.