You may have some sort of power problem with the scanner. Can't say what's going on with your DVD drive, as that may be just a coincidence. I can say that if you have uninstalled and reinstalled the drivers, disconnected the power supply and reconnected it, connected the USB cable to a different USB port and it still would not function, then it probably is dead.
If you go into My Computer --> System Information --> Hardware tab --> Device Manager, then collapse the plus sign next to Imaging Devices, is the scanner listed there? Does it have a yellow question mark next to it (meaning there is a problem with it)? You can try updating the driver from there if you'd like to give that a shot.
I do know that when a scanner goes through preview, it takes a "snapshot" where the optical bulb does not actually move the entire length of the bed (which is why previews show almost instantly vs. a full scan). If there is something wrong with the motor that drives the light unit, then it can't do a full scan. Does the light come on in the scanner when you restart your computer (most scanners go through this self-test), and do you receive any kind of error message when it fails to scan?
Again, if you do need a flatbed scanner, they are not expensive. The model you have has been improved, and there are models on the market now that scan at much higher resolutions, are much more compact, and are quite a bit cheaper (as I said before, I got mine from Amazon for $79, qualified for free shipping, and there was no tax). I use mine maybe once a week (which is extremely light), but it was worth replacing when the old one kicked the bucket and became a rather large doorstop.Edit
: Have you tried plugging the scanner directly into a power outlet in the wall (and not through a power strip or battery back-up unit)? If I recall correctly, I had an HP printer that acted up a while back; when I plugged it straight into the wall, it worked. Through a battery back-up unit it would not (even though the lights were flashing that it was receiving the data from the computer). Apparently it wasn't receiving adequate power unless it went straight through the socket in the wall.
Edited by txtchr, 03 July 2009 - 02:02 PM.