you have got about 4 years out of that one.

I wouldn't even bother doing much "troubleshooting", I would just replace it. Newegg.com just happens to be having some pretty good deals on DVD writers with free shipping.

To give it one good test though, put a bootable CD in the drive and shut down the PC. now reboot and enter the BIOS to ensure it is set to try to boot FIRST from the CD drive. If it boots and runs fine for a while try a commercial optical drive cleaner - if it doesn't replace the drive.