+ 0 Votes Are you getting any failure message? seanferd 5 years ago Are you using a recovery partition, or CD?If a CD, are you using the OEM CD that came with the system?Is this you?http://www.tomshardware.com/forum/252436-31-windows-repair-install-failsIf you have changed hardware, and are using an OEM CD, you will need to have the drivers for your new hardware ready to install at the beginning when it prompts you. + 0 Votes Also remember.... ThumbsUp2 5 years ago ... during install, at about 39 minutes if I remember correctly, Windows will reboot. If the CD is still in the drive, it's entirely possible you're either pressing a key to make it boot to the CD, or it's automatically rebooting to the CD without you touching the keyboard to make it do so.Have you tried opening the CD drive door and removing the CD when it begins this reboot, just to make sure it's rebooting into the repaired OS and not to the CD?To answer your question, no... it is not possible to undo a repair install. You can wipe the hard drive and start all over though, loosing all documents and pictures in the process. Best get the repair install to finish first.