HDD Replacement

I have a original Xbox one, and decided to upgrade the standard 500gb hdd for a 2tb sshd. Well I go into it and swap the hdd and followed the correct steps in setting up the drive and getting the OS loaded back onto it and put it back together and all, then it stops working as it should, boot...

I'm planning on buying a new cpu cooler since my cpu is running hot and I was about to buy this http://www.newegg.ca/Product/Product.aspx?Item=N82E16835181030&_ga=1.228753694.306587643.1425325478 but I wazs wondering if I needed to put therma paste on it .So basically my question is Do you need...