Windows 7: Power Outage During Win 7 Upgrade

Sounds like it is trying to repair either Vista or Windows 7. Does it say which? Try running Windows 7 Repair, or If you have a Vista DVD and can get it to boot (or run Setup from the CMD) then you can try Repair My Computer on the second screen. See if it finds an installation to repair, then accept the repair, plus repeatedly click through to Startup Repair to run at least 3 times with reboots.

Your best course of action here is to try to get your Windows 7 DVD to boot by resetting CMOS or updating BIOS, to get the DVD drive to boot first and keyboard to respond. You can also trigger the DVD to boot by tapping the key given for Boot Menu on BIOS boot screen.

If this fails, then you need to run the Diskpart commands given to wipe the HD to force the DVD to autostart, or if unable to run the commands, boot free Partition Wizard bootable CD (it should autostart) to delete the HD, create New partition, then format NTFS primary. This will also force the DVD to autostart.

Thanks for your help Greg. I think the computer believes Windows 7 is the only OS installed, since that's what comes up when it was trying to boot between the OS and the rollback. I'll try and get this sorted tonight.

edit: It turns out I had the halt keyboard on error setting enabled in the BIOS, which was giving me grief. It couldn't manage a system restore, so I'm currently formatting the hard drive with the diskpart commands you gave me. Thanks again.