"Being charged 2 hours labor to replace a £5 is the sort of thing you associate with dodgy mechanics and rip off TV shows."
If you don't have a spare mouse, how do you diagnose it? Actually, that is a good question. Unplugging the mouse and the problem goes away just shows that it's a problem somewhere along the line. Could be OS or hardware. But the mouse looks OK, and if there's no sign of damage along the wire then it isn't so obvious. The only way I can think is to download a Linux Live distro and fire that up.
I'd have tried a new mouse before reinstalling Windows, but it might still be quicker to do that than go and get one.
The two hours' time isn't for solving the problem, it's for finding it.
Biting the hand that feeds IT
