Clean install or Upgrade my System Unit?

Hey guys,
I'm in need of assistance right now. I just rebuilt my computer and changed everything including my CPU, motherboard, RAM, Power Supply Unit and my GPU. But the Hard Disk Drive is still in use. The problem is, whenever I turned my computer on, a BSOD will appear. Maybe it is because I installed Windows 7 on my old motherboard.
I have a Windows 8 disk with me. I want to know if I can just upgrade or perform a clean installation since reformatting my hard drive is my last option as I have lots of data that I do not want to lose. If I choose to upgrade, can it fix all the issues that I am facing right now without losing everything?
