[Dante Hicks]

I used to work for a PC Warranty company which used to deal with situations like this. The key wasn't some sort of boiler plate legalese, but simply applying a rule of common sense/reasonableness.

So if an engineer attended and replaced a motherboard, and the PSU blew the next week, it could well be because of our job. So covered. But if the mouse button brokes, or the monitor's power failed it wouldn't be covered. The actual component we installed obviously had some sort of warranty on it.

But with regards things like spyware it's a lot more unclear. Someone could completely change every single file on a HDD ten times in a couple of days, and therefore problems could reoccur far more often than a physical fault. However, the same sort of estimation would seem to apply. If you were really arsey you could do some sort of screen shots / directory listings / registry backups or something like that.

However I wonder what the point of the question is though. If you need to resort to "cleverness" to try and avoid fixing customers problems then you're probably not doing very well anyway. My rule of thumb when helping people with their PC's that if the problem reoccurs in 90 days (irrespective of who's to "blame") I'll fix for gratis. Most people end up paying anyway but it's nice to give them an option.