Mac desktops forum: Mac mini with severe problems

I'm trying to help my sister-in-law get her computer to work. She reported that when she boots it, all she gets is a blue screen. It is an early intel mini running Tiger. I believe that it has 1 GB of RAM, but I'm not sure which processor. It is still running the first version of Tiger not updated. She only uses the mini for email, word processing and simple games. However, she never shuts it down properly and her autistic grandson loves to punch buttons and is sometimes not supervised closely.

She unhooked everything and brought it to me. I hooked it up to my monitor and mouse and ran TechTool Pro on it. It passed all the tests (most exhaustive set). So I tried to boot and it jumped from loading OS X to the blue screen in the middle of the progress bar's run. I left it for over an hour and nothing changed.

I booted it with my own copy of the Mini's install disk (mine is just a few months older than hers) and ran a permissions repair. The report said that a lot of things that sounded serious were fixed, not just the usual things that I see. I should have written them down, for I cannot access them now as the restart afterward ended with the same blue screen.

So I tried a clean re-install. The first install disk does its thing and asks for the second disk. Near the end of the second part of the install, an alert said that an error had occurred and to re-install. I tried not once, but two times. It always stalled at the same place and then had to be shut down by removing the power cord. If I just shut it down with the power button, when I try to reboot, after any interval, it comes up asking for the 2nd install disk. The disks have to be removed by holding down the mouse button during boot to get them to eject. I let the installer verify the DVDs the first time through, so it shouldn't be their fault.

Is there anything that can be done with this?