The cd rom on my laptop wont read cds or dvds?

usually when i put a cd into my laptop it asks if i want to install it onto itunes and wmp comes up, but now it doesnt do any of this. i go to my computer and click onto the cd rom bit. and it says please insert disk, even with a brand new cd :S any advice on how to fix it? or has anyone else had the same problem? chers :)