I'm going to look at a G5 dual core 2.0GHz mac and would like to be able to run a hardware test on it before I buy it at least. The seller doesn't have the original installer CD's. What else can I do to check the system out before I buy it?
If your asking on how to do it:
All you'll need is the system discs, i think its usually on disc one with the OS installer. Just boot the computer insert the disc, restart and hold the option key down while the computer boots. Once you get the gray screen with the buttons on it [if booted correctly, you should have your OS, the OS X installer disc, and the Hardware Test].
All you should have to do is boot the Hardware Test. Click on that button. Once, up and running you will have the option to do the Quick Test, or the Long Test.
If he still has AppleCare, you can download TechTool Deluxe from Apple, but he has to have active AppleCare [which i think he might not].
Its by another company, but its Diagnostic Software, which should do the same thing.
It was from this Apple Discussion.