Power?

The strangest thing just happened: I’m in the case of my desktop taking out the old modem card, because I don’t use it anymore and I have no free PCI slots. Actually, I do have one free PCI slot but whenever I plug anything in it freezes my computer, so I try to avoid it. Anyway, I was swapping out the modem card for a firewire card, but while I was pulling out the modem I heard thunder and the computer started turning on! I immediately reached for the ‘real’ power switch on the power supply but I forgot that this case doesn’ have one, so I unplugged it. The card was half out of the PCI slot when this all started so I was very worried that it would hurt something, but it seems everything is alright. This has been the strangest day.