Ok guys, at my wits end here. I think I've tried everything. This isn't really a Fedora problem, or even a Linux problem, but I know a lot of you guys are pros, maybe someone here has an idea/can help me troubleshoot this:
My laptop will regularly and predictably die - as in turn off/hard power-off while in use. Here's what I've tried so far:
At the suggestion of Dell tech support, I ran the Dell BIOS diagnostic tool (hold Fn at boot and use the built in tools). I also tried the one from the website. I also thought it was heat - cpu and gpu seemed to be running a bit hot. I recently warrantied the Dell motherboard, and thought maybe that the guy who put it in didn't put the heat-sink crud on there. I pulled it apart, reapplied the heat-sink goop, made sure the fan vents were clear while I was in there. Things began running much cooler. But the problem persisted. Then I got a Dell utility that lets me manually control the fans, and cranked them up to full-speed all the time. Things were running very very cool, high 30's low 40's C. The problem persisted. I thought perhaps it could be a bad PSU (I know it's a lappy and it should be ok, but anything's possible), so I tried running on just battery power. Still getting the shut downs. I ran the Dell BIOS diagnostic, it says everything is fine. I tried reinstalling my OS - actually, I even switched OS's. Same problem.
There are a few ways I can guarantee it will shut down: watch youtube clips, make a skype video call, or let the kids play flash games on it. I want to say maybe the onboard video card is bad, but that is why the motherboard was just replaced (as in just a month or so ago). This happens on the current 64 bit OS I'm using, and the 32 bit OS I was using when all this started.
System specs: Dell Latitude D830, 2.2 GHz Core 2 Duo, 4 Gigs of ddr2 PC5400 RAM, Nvidia Quadro NVS 140M 512 MB. Currently running Ubuntu Hardy 64.