Take the hard drive out from the dvr and hook it up to your desktop.
Use defraggler to find out some information about the hard drive.
Click the health tab and it should be able to tell you what brand it is what format it has and disk health.
Use that same format it has for the newer hard drive when it comes.
You can try a seagate if you want to, but make sure the model your getting is reliable and will work with the receiver itself.
You may not like this idea, but call dish network technical support and see what they recommend first hand.
Lastly check the connectors on the hard drive itself and cables on the hard drive.
You never know when a cable might go bad and it may not be the hard drives fault.
Had that happen once and awhile. :/