Can't access DVD to install W8 over XP.

HI Guys, I am trying to install the W8 DVD over the current XP OS, but in MyComputer, the DVD Drive isn't listed in the tree view. Device manager says it's installed properly and functioning well. My Q is this: how do I run the installation DVD from the DVD drive using the Command Prompt. On Windows Start-up I hit F12 to access the boot order, and when I arrowed down to the DVD drive and hit...