I decided to give ubuntu a try and chose to replace windows with 13.04. After the install i removed the disk and restarted and it says there's no boot disk or that it's a defective disk. When i put the cd back in and restart it, it boots and starts ubuntu. I've checked the boot priority and installed boot-repair successfully, but it still won't but without the cd. The system is a gateway win8 desk top that's about 5 hours old and worked fine before the install. Any help would be very much appreciated. Thanx.