Vista - Medieval 2 and Counter Strike Source problems.

Hi everyone, I bought Medieval 2 total war Gold Pack (which includes the expansion) recently. When I put the installer disk into my DVD Rom, it wont read the disk. It doesn't even detect that it is there in the first place. Can someone please help me because I have been really looking forward to play this game, only to find out I can't even install it. Also, I bought Counter-Strike Source, along with Garry's Mod 10 at the steam website. however, my computer freezes when I play both games, crashing anywhere from 5 minutes to 2 hours. Sometimes, I get a blue screen, sometimes it freezes and I have to cut off the power supply, and sometimes it crashes to the desktop.