That has happened to me. Troll cat has been busy! 

Absolutely true. I'm typing this using the on-board VGA.

Well, a hard shut down can wreak havoc with the current in components. Usually, no harm done. Too many times and a dose of bad luck though, and a transistor or capacitor is likely to eventually blow. Especially with dodgy cards or power supplies.

I was not aware that holding the power button down for extended periods could damage the graphics card.

Or did troll cat sitting on the ventilation cause it to overheat?

The power button on my UPS is recessed.[](/ok)

Curse you troll-cat!