Is this a client who's paying you? I've had a few like that and we used to just tell them how long it will take at £90 per hour to fix... "Oh I could get a new one for that"... yes, you could and we have stock!
Hmmm, yes, I've had one or two like that as well. Just graphics and network drivers were an absolute sod.
Has it at least got USB? Tell him to get a wireless dongle and stop bothering you!
If you want something durable, you might want to take a look at Lenovo's ThinkPad. They are beasts. I've seen some take quite beating, and still work. Of course, it doesn't eliminate the possibility of getting a lemon, but in my, admittedly somewhat limited, experience, ThinkPad are really tough little machines.