Liteon cd&dvd drivers undetected

Yo,

A few months ago, I was watching dvds and burning cds on my computer. Now, my cd-rom drive won't work, and neither will my cd/dvd-rom combo drive. They do not show up in "My Computer". They show up in the Device Manager, but they both have yellow triangles next to them that contain an exclamation point.
When I put a cd or dvd in the drivers, they make the noises that a computer should make when you stick a cd into a working driver, but that's all it does. It won't play cds or dvds. I've tried uninstalling and reinstalling the drivers and it didn't work. So, I tried updating the drivers, and that didn't work either. I've tried looking for information about how to fix this problem through google.com, but all the answers that could have been helpful were for people with windows XP or Vista. I have windows 2000 professional, so none of the online threads I've found are helpful. How do I fix this problem?