PC freezing on start up.

[Ja'chyra]

Sounds like a corrupt data file. Next time you get it on, I recomend uploading all important documents to a data storage spot, and wiping your HD clean and starting fresh.

I've changed the hard drives for new ones and re-installed the OS from a different disk and it still happens.

Can it go safe mode? Or Windows diagnostics?

Nope, it freezes on the green bar screen and wont move from there.

My first thought was obviously the OS but it can't be that, my only other thought is the motherboard but I don't see how?