First of all, welcome to BC !
It is possible that there is a problem with your RAM, but since you merely replaced a hard drive this is less likely. What is more likely is that somehow you have installed an incorrect driver, or missed an important one.
If you can get your computer to run at all, I would like you to download and install Speccy, which you can get for free from here, free :
When it is installed, run it and post a copy of the report URL inn your next post. These two images will show you how to get the the URL -
If you have a problem with this, or cannot get the computer to run at all, post back with details of your computer.
Edited by Chris Cosgrove, 26 October 2014 - 07:22 PM.
Topic moved to Win 8