My client, a single mom, shut off her Internet dial-up and after 6 months, got DSL. When she tried to turn on the eMachine system, plugged into the AC power that whole time, it was dead, though the monitor light came on.
The PSU was DEAD, as was the FIC AM37 mainboard. No visible evidence of the "capacitor plague" where Taiwan manufacturers kept selling known defective parts for upto two years after they knew the parts they stocked and used were defective!
Evidently, power spikes can affect all computers and monitors, even when the system is in the 'OFF' state, as long as it is plugged in! The PSU has no power switch. Even then, in all the PSUs I have dissected, only the "hot" black AC Power wire is disconnected, and Ground and Neutral remain connected. Monitors and TVs only blank the screen. All the electronics parts are still powered.
The CPU and DDR memory stick and the Hard Drive and CDrom are good, as tested in a different machine. We will be buying a different brand mATX board to replace this one, at a cost of about $48.00. A new PSU cost us $20 on the Internet. Of course, it is a 450 watt unit, for this AMD Athlon 2200 XP processor.
We are in Central Florida, and power can be horrid. There is no 'grid' as power plants are arranged like dominoes ready to fall over.
Recent power monitoring over two months of our residential lines ( by Progress Energy Corporation, with two different computer systems, at the transformer and at our new Square D entry, I installed, to replace the failure prone Federal Pacific junk from 1980 ), showed 50,000 'hits' or spikes, of voltages above 17,000 Volts, each hour, and, we did not have any lightning storms in the three day periods of monitoring each week over those two months!
I have continued to preach to everyone, since my stint as an engineer covering EMP (Electromotive Magnetic Pulse Discharges - Lightning, inductive spikes (from motors on the lines, refrigerators, Dryers, Washers, and static discharges) in 1987.
You NEED to spend the $39.00 to buy a 500VA (350 Watt) Uninterruptable Power Supply for computers, if you live in Florida or Washington State, both being Ground Zero for record Lightning strikes!
Anyone who lives in a Northern Temporate region needs a UPS to protect from seasonal brown outs, too.
Hey, I'm running a dozen in my home, right now, because of Progress Energy's policy of switching generators every 12 hours, causing 3 to 6 brown-outs during each! I do not have blown up TVs, VCRs, Computers, Printers, or satellite and cable controllers, like some of my neighbors suffer!
When you turn 'off' your appliances, computers, you might remove the AC power plug.
Get a UPS, and let it protect your valuable computer, and entertainment, systems!