The media (CD disk) could be bad or the CD/DVD drive is dirty and is not reading it correctly. I use to have problems like this a long time ago doing Windows OS installs/upgrades. Get a CD/DVD cleaner disk and clean the drive then retry. I would sometimes go through 4 or 5 tries before it did the entire install to the end and the final boot up. Also, pull out everything non-essential and just have the HDD, CD/DVD drive and Video card connected No sound card no extra USB card no nothing else. Then retry the install. Also if the MoBo has built in video go into the BIOS enable it and yank out your Video card then retry install. See if it works.