Make, model and since you did make it to the BIOS screen did you change the boot order (sorry but no make or model so advice must be generic) to boot from the CD/DVD first?

Tell more. Tell what the words in red ask for. Tell what boot disk or dvd you have to work with. And tell what words you see on the screen.

-> And JUST IN CASE. Have you cleaned your machine EVERY YEAR? Example at http://reviews.cnet.com/4520-11319_7-6240575-1.html
Bob