My CD/DVD multidrive stopped reading DVDs?

I have a gateway laptop with a CD/DVD multi drive. One day when i put a DVD in it it wouldn't read it then when i put a CD in it it was fine. I've never had this problem i've uninstalled it and reinstalled it and i still have the same problem. I have a few virtual drives but i've had them before and they never affected it. I whent into the Drive to see what drivers it had it only had a few like cd.sys i remember seeing it awhile ago and it had a dvd.sys so i'm wondering if someone the drive got corrupted or my anti virus removed it by accident. how can i fix this? I've tried using my Windows CD to reinstall everything but it gives me a error when i try to use it saying something about my system restore files are corrupt. I REALLY REALLY DON"T WANT TO TAKE IT TO GEEKSQUAD i gave it to them for a broken key and it took 2 months and when i got it back it had even more problems (more broken keys it wouldn't boot up crap like that) what should i do?