I've already installed 20 odd games on my computer without any problems, Raze (Old games I know worked before and wanted to test on the new system, mostly - but a few other new games, too). I know beyond question it's not the drives or any other hardware problem.
Can't be a bump in shipping either, as the computer was assembled in the room where it now stands by a friend of mine who knows pretty much everything there is to know about computer building.
I'll try copying the DVD contents onto my drive, though I'm not hopeful it'll let me install from anything other than the disk. Still, has to be worth a try. I'll report back in this thread if it works.
Thanks for the suggestions
