Ubuntu

I tried to re-install Ubuntu to my Toshiba laptop computer, but now I'm thinking I should have waited. I downloaded the Ubuntu download, and burnt it to a disk. Then I followed directions, at least to a point. I had chosen the icon with one disk, after pressing F12 ( pressing F12 like it said to do at start up). It seemed to be doing fine to a point until the loading thing stopped loading completely. I waited, and got nothing else. I switched it off and turned it back on and now it's not doing anything, the disk won't eject, nothing is showing up on the screen. What did I do? How can I fix it? If I take it to someone how much would it cost to fix?