Please remember that any mention of competitors, hinting at competitors or offering to provide details of competitors will result in an account suspension. The full rules can be found under the 'Terms and Rules' link in the bottom right corner of your screen. Just don't mention competitors in any way, shape or form and you'll be OK.
Nope - you won't need to reinstall windows.
Just make sure that the settings in the BIOS are reset to defaults (CMOS reset is a good idea).