Elmer,
Sounds like a FIX, Eh?
But what's making the hair stand up on my neck, is your comment, "At some point I crossed my legs and banged the case with my foot ".
You gotta be kidding me. The computer is sitting on the floor? Boo BAD!
This PC sat on the floor too,,,,, until it overheated and CRASHED.
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I've never understood, taking the most delicate, sensitive, high tech, electronic device in the house and putting it on the floor.
It should NEVER be on the floor. It should have a place of prominence depicting it's cost and importance.
A swift kick can also cause a hard drive CRASH. I just scrapped out an HP PC that was sitting on the floor and got kicked once too often.
Anyway, back on topic, I don't know of any component in a PC that would or could be damaged by a magnetic pickup tool scavenging a loose screw from the bottom of the case.
I once tried to erase a floppy disk with a magnet. NO GO!
PC's are pretty much impervious to small magnets. Just a thought.
Cheers Mate!
OT