New HD won't boot

[FlashDude]

How big was your old HDD? This may be a size limit problem.

 

[Lowri]

The old drive was at least 500 gig...I'm getting a new HD because the old one filled up

 

[saltynay]

Stating the obvious here but you do know you have to install windows onto the new drive for windows to work. Why are you taking your old one out? Just run both simultaneously if its the new hdd which is the issue it won't matter as the old one is the one booting into windows...... Check the bios and see if the hdd is actually supported and listed.