I have the Polaroid DRM-2001G

Overall, It was a good machine, but now it won't record from HDD to DVD.

My question is Can you take the HDD from one machine to another?

From one Polaroid to another polaroid?
From Polaroid to another brand??

I have a bunch of stuff on the HDD.

Danny Phantom, Recess,In the heat of the night, Blade. Once I put them on the HDD, I deleted them from my DVR. So I can't get some of that stuff back

With some recorders, you can.
Check out this forum on DVD recorders: http://www.avsforum.com/avs-vb/forumdisplay.php?f=106
They are the experts. You can find out anything. There's a thread on the model you have. You may want to post your question there - someone will come along with directions on how to do it!! ...or find a fix to the problem.