My friend's Dell laptop was working fine until one day for no apparent reason, it wouldn't power up. The power adapter seems to be OK, I measure 19.5 volts DC on the plug. When I hit the laptop's power switch, the green LED on the adapter just fades out and nothing whatsoever happens on the laptop itself.
This is a PIII which I installed Ubuntu on for my friend, and he let me use it for a month on a trip. I feel responsible for it not working, and want to try fixing it. The battery doesn't seem to hold a charge, so I had it plugged in most of the time. I suspect it's a bad jack for the power input, since the plug is vulnerable the way it sticks out, but why would it just suddenly go like this with no warning? Any ideas?