Quick question about windows 10

[Laserer]

After I used my free upgrade for windows 10 my motherboard and CPU died so i had to get new parts. When i put the new parts into my computer the free upgrade licence did not transfer over now it keeps on telling me to activate windows 10 does anyone know how to activate windows without buying a new key?. Also there has been pixels flickering on my screen and I know its not my gpu. could this be a software issue?

Specs
Msi GeForce GTX 660
intel i5-4460
gigabyte G1 gaming GA-Z97MX

 

[glamdringfh]

You'll need to contact Microsoft Support to get your key unflagged at this point.

If the pixels are a new development it might be a driver issue, but it sounds more like a hardware problem to me.