When you made the image of Win 7, did you create the repair CD in addition to the image? If so you have to start the computer from this CD to restore the image, if you didn't then make the disc and start the computer from that.
I know you have mentioned using the DVD, I'm assuming you refer to the installation disc. Trying to use the restore function from within Windows wont work, you have to use the repair CD.
You do realize this will restore completely, the original installation, together with any problems it had. Your current installation will be overwritten.
Computers... designed to entertain,help with work but most of all to frustrate you!