If you tried to install Windows 7 or later, your original install is in the windows.old folder. It was moved there before any other operation was performed.
The install may have failled because there is not enough space for the windows.old folder and all the new files that need to be copyed to your drive: You need AT LEAST 50 Gb of free space on your main drive to upgrade to Windows 7, probably more if you wanted to install Windows 8/8.1.
If you can't restore, you can try this:
Boot from a Linux live medium, like a live CD/DVD.
Look if you have a windows.old folder.
If you have one, DELETE every other folders from the main drive.
Move the content of the windows.old folder to the root folder.
Reboot normaly.
The windows.old folder is a safety net in case the new install fails catastroficaly.
Another option would be to move the Windows.old folder to some external drive, reformat the main drive and do a clean install of the new version. While moving the windows.old folder in preparation for a clean install, you don't need to move the content of the windows.old\windows folder and sub-folders. You may want to keep this folder: windows.old\windows\font as it contain any font that you installed along with the one provided during the original install.
In any case, the factory restore partition will no longer be usefull and only waste valuable disk space.
Unhide it, delete it's actual content and use it for your personnal files.
Electro, May 2014
