I think you have been more than reasonable considering the computer is years out of warranty. Though we all like to help, there is a limit to one's good graces especially when being abused.

When I come across issues of continually corrupted registries or system files, I immediately start looking for:

1. Hardware defects, especially bad RAM, bad processor caches, bad hard drives, etc...

2. Software that is corrupting things. Who knows what this kid is trying to do on this system.

At this point I would offer to try and resolve the problem, but I would not do it for free. It would be normal labor and parts rates from this point on.

You've done enough.

TL