New
#11
Ok, your disc worked once, thats a plus... so I'd start with the easiest solution, and that's to clean and buff the disc. You probably threw it somehwere thinking you wouldn't need it again, and it got smudged. If their are scratches, toothpaste works wonders by filling up the top-most layer of plastic that is prone to them.
Next, is to find another DVD reader, see if one with a stronger lense can read yur disc.
If your stilling hitting issues, try re-downloading, and re-burning the ISO. Nero works best, but there are other good programs out there. Although, I would recommend the USB method overtop all else. There is alot less data-loss when you move the files to a drive, then burning to a DVD. If a large enough thumb drive isent possible for you at the moment, my second choice is a DVD-RW, it has a higher data-retention rate, becuase the data-writer can fix mistakes as it burns. It's also what M$ uses to test the DVD-burn-then-install scenerios.
Try the above, and let us know how it goes!
-D