Since you need to be in the OS to do a Repair Install, that will probably not work. But we need to know where you can go when you boot to the Install DVD? If you can boot to the welcome screen with the repair computer on the lower left, then click that and try a Startup Repair.
If you can get into the WinRE scenario by using the F8 key during boot, that will take you to almost the same place.
Since it sounds like your drive may have been corrupted with the power glitch, perhaps running Chkdsk would help. But if the corruption is more than the system can handle, this is where it is really good to have a backup image. If you don't have one of those, you may have to reinstall, or if the system has an image you can use to get it back to the original condition.