Continual reboots on PC

I work part–time night shifts in a care home for people that have learning disabilities. A few months ago, someone donated a PC for the use of the house mates. It came with XP pre-loaded and had the usual array of low-level games, which people enjoyed playing.

However, due to people not closing-down the PC correctly (I think), the computer has developed a fault in that it does not fully boot into Windows – in fact, it just keeps re-booting!

The screen display is hard to describe, but looks a bit like a scrambled array of Boolean – type characters! You can see the POST booting-up phase through this muddle of characters and just make out the loading bar of XP starting, but that’s as far as it goes, as it then re-boots itself to the POST phase and this scenario just keeps repeating itself, over and over.

One night I managed to get it to fully boot into Windows and did a system restore to try and get it back to a time when it worked. I've tried "last Known Good Configuration" as well. This was successful until the PC was powered down, but on a fresh boot-up, things were back to square one!

I’m thinking that a fresh install of XP might fix things, but nobody seems to know where the disk might be (if indeed, one exists at all?). If there isn’t one, I doubt whether management would shell-out for an XP disk, as the home is run on a strict budget (especially at the moment).

Do you think this is purely a software issue, or could it be a fault with the hardware?

I was thinking that a free distribution of Linux installed might be an answer, as it would at least give them a PC that has a few low-level games on it (which they loved to play under XP). The PC would not be used for much else, as the cognitive skills of the home mates are quiet limited due to their learning disabilities. Any solutions, thoughts on the problem would be appreciated.

Dave.