Restart it, When you get to the select your language, don't do it. Hold down shift and Press F10. You will get a command prompt. type diskpart and press enter, and wait for the window to reply diskpart. Type list disk and press enter, you should only have one disk, disk 0, if it shows the DVD you should be able to determine the disk # diskpart assigned it,but it should be disk 0, so type select disk 0 and oress enter (#0 not the letter) it will say, disk 0 is the selected disk. Type clean all and press enter. Then go have lunch, assuming you computer does not crash it will be several hours to finish. When finished it will say diskpart cleaned the selected disk. Type create partition primary and press enter, it will say partition created, type format fs=ntfs quick and press enter, it will tell you it formatted the disk. type active and press enter. it will reply it marked the partition active. Type exit and press enter. type active and press enter gain and you will be back at the select your language screen, the continue with the install, the disk is completely clean. Nothing survived. If your computer made it that far, you should have no trouble installing. Anything you don't understand, just ask.