[ubuntu] Can't boot from CD anymore because of Ubuntu

view story

http://ubuntuforums.org – After having some problems with Windows 8 not working anymore etc (worst OS ever) I decided to go for some nostalgia and use Ubuntu for some days, and even see how it was after Unity was introduced as an old KDE user. I installed the newest Ubuntu and well, to say the least I had a lot of problems, such as automatically logging out when I opened a video on the computer, flash player constantly crashing etc. So I wanted to go back to Windows 7 and I burned an ISO ready to put it in. I was astounded to realize that the PC just wouldn't load the disc for some reason. It did so when I installed (Hardware)