HL2 works with CD, crashs with DVD

[Eveready1]

I have the retail DVD version of HL2 and have loaded the latest update from steam. I could never get HL2 to run. Rather, it says it preparing HL2 dialog for a couple of seconds then disappears. But when I borrowed a friends CD, HL2 worked perfectly. Thus, I'm assuming all of the of the HL2/steam code is correctly loaded. The only difference is instead of the DVD in the drive I have a CD version of HL2 in the drive!
One related or unrelated issue is since I loaded the update from steam, my other games such as Counter-Strike I can't connect with a server.

 

[Killing2Live]

you prolly just have a bad reader and has a problem reading dvds or something, do you have any problems playing movies or other games in dvd format?

 

[Eveready1]

CD burn and read well. I can play store bought DVD movies well. Sometimes when I make a movie it screws up the DVD, I'm not sure if it the DVD software or the hardware.
Is there any way that I can determine for sure that it is the DVD reader? It is not the DVD media since, the store exchanged my orginial DVD with a new one. I have a optrite DDC0201 dcd reader/writer. Thanks

 

[Killing2Live]

well if it can play store bought dvds its prolly not the dvd reader but i dont know