I don't want to belabor this point, but you have to restart your Mac while the restore DVD is in the drive, and hold the C key so your Mac boots to that installer disk, not to your hard drive. If you are OK up to this point, then open Disk Utility from the menu, _select your hard drive_ from the list on the left. You will then be able to click on the Repair Disk button.
Do you have more than one partition on your hard drive? You will easily see that in Disk Utility.
Keep in mind that you won't be able to completely repair the disk unless it is a Mac formatted partition, or fat32. You can't repair an NTFS format partition for Boot Camp, for example.
You should see the partition information at the bottom of the Disk Utility window.