Are you rendering to disk first, or trying to go straight to DVD?

Try rendering to disk and use a DVD program like Power DVD to check if the files on your hard drive work as a DVD should.

Have you ever managed to get an MPEG output? If so what has changed (other than the new drive)? Have you tried a feature for the first time?
If yes to either of these, try again without the changes.

If you have had the problem only since the update, re-install to the previous level.

I have Studio 8 with an XP2100, Radeon 9000 series VGA and 512MB RAM and Studio (now) works fine.