Nick Arno :
Title pretty much says It all. I would prefer not to lose all my stuff again.. Will I need to reinstall windows when I upgrade those parts. I'm not changing the mobo.
Nope. Not at all! I do however recommend making sure you're bios is up-to-date for that CPU to be able to function properly also make sure to remove all drivers IF you switch from say AMD to Nvidia. But If it's the same your fine!
All-in-all, you don't need to re-install.