CD/DVD burner not working

Hello.

I'm having trouble burning DVDs and CDs. For DVDs i use ConvertX. It goes through the converting process; however, when it starts burning, it ejects the disc. A message pops up saying the discs are incompatible or another source is using the drive.

Last week my pc was infected with Maleware Defense. I removed the Maleware, but can no longer burn DVDs or CDs. Not sure if it is related but it worked fine before, and I am burning from the same pack of DVDs.

Thanks

Update:

Okay so I can't play DVDs either. I get this message when I try.

"Windows Media Player cannot play the DVD because a compatible DVD decoder is not installed on your computer."

Hello,

Use VLC, Windows Media Player may not be able to play because the disc is protected.

http://www.videolan.org/vlc/download-windows.html