My old laptop from 2006 was constantly being hacked due to my use of Limewire and torrents,going to unsafe websites, and not using any security causing it to constantly crash. I think when I left it plugged in during a lightning storm, it got hit and it roasted the motherboard.
My old computer's modem got blown out by a power surge. I got the modem replaced. The last straw was when the fan started making weird noises and then the computer overheated and shut itself off. I could not get it to turn on after that.