I have had zero problems with it and my Tyros is up all day hooked up to my PC all day which is up and running and neither has locked up yet.

What I would say is this....tell you buddy unplug the Tyros and watch the pc for a few days and see what it does, then plug the Tyros back in and see what it does.

Try repeating that a few times and if it keeps locking up when the Tyros is plugged in then....I would say the next thing to look at is what o/s the guy has and what else if anything is running at the same time etc.

An example for me...with Norton Anti virus running....my Sonar software just will not run at all, my point being investigate a bit further, shut things off that are running in the backround on the pc until he finds the mismatch.
Terry