Here is how it goes, I have a TV card in my computer and a cable connection, It used to work fine but i disconnected the cable for a couple of months and then when i wanted to reconnect my cable to my pc, it started acting wierd, first off as soon as the cable touched my P casing it gave a huge spark, like not one of those ordinary sparks but a really bright spark as if i was actually touching a live electric wire with my PC casing.
I also noticed that once i touched the cable with the casing and after the spark the cable was kind of attached magnetically to the casing body, like i had to apply some force to disconnect the cable that was just touching my PC, like either the PC or the cable had some magnetic properties.
K so I ignored that spark and connected the cable, after a few seconds smoke emitted from my PC and it fried the power supply.
The cable is a common co-axial cable used for cable transmission. I used the same cable in my television and it worked fine.
I also gave the TV card to my friend and he tested it out on his PC and it did not give any errors or any sparks. so card is fine too.