After installing Leopard cd burner wont work

I installed 0S 10.5 on my eMac months ago, I immediately updated to 5.1 and then noticed every time I tried to burn a Music or data cd, it would say it was burned, but the disk was still blank. I was patient and have since updated to 5.2, yet the problem is still occuring.
I burn the cd, and wait until the computer says it is finished, but when I go to play it its blank so then I try putting it back into the computer to see if I formatted it wrong or something, the computer then shows a stop sign and says it cant be read by this computer.
This NEVER happened prior to installing leopard
how do I fix this?
did anyone else have this problem?

Try running the Apple Hardware test. See if it's a hardware problem first.
Also, check System Profiler for status of the optical drive and check the logs as well.
http://www.thexlab.com/faqs/aht.html