DELETED CD/DVD PLEASE HELP!

Hello,
Can someone please please help, i got my computer reformatted and since then i can not play dvds as it asks me for a suitable decoder or something. I read about drivers and done driver detective and found out that my drivers are out of date, but when trying to fix them it asks me for a product key> Also i went to my computer. right clicked went to manage and uninstalled cd/dvd and now thinking what have i done....Not very good. Its an acer travelmate 2410. CAn someone please send any free download sites that are easy to use. Would be delighted. Getting Drained now. Thanks so much !!!