I did that before, happened when I was trying to connect a 1/4 inch cable, jacked into an 1/8 inch plug fed into a crappy Soundblaster card. I was trying to get the plug into the card and bang everything blew on the card. Not sure why it happened but I upgraded to a proper soundcard that was designed for taking 1/4 inch guitar leads and everything has been cool since then. Bummer about the card man, at least now you can look for a good quality one made with guitarists in mind.