Boot Drive Problem?

[RayAIRSPro]

About a year ago, my friend bought a prebuilt pc with pretty bad specs. I have helped him upgrade everything including the case, graphics cards, and ram. Recently, due to the fact that his CPU was bottlenecking his GPU hard, I helped him upgrade his motherboard and processor. When we booted up the pc, it loads everything fine, and shows the motherboard bios and everything. Then, when we try to start up Windows, we just get a black screen with a white blinking cursor on the top left. I feel bad about this, and I hope I haven't broken anything. Does anybody have any solutions to this? Thanks!

 

His system specs:

Processor: FX-8350

Graphics Card: Stock GTX 970

RAM: 8 gb of generic ram we found at the local pc store

Storage: 3 tb WD HD

Power Supply: Dynex 520w 

[Vegetable]

Generally you have to reinstall windows if you get a new motherboard, just sayin.