ive been working on my cab pc for a while now..tweaking software, adding games, etc. i had finally gotten everything all fixed up and worked out, and ready to put back in my cab. i powered it up, and there a few things i wanted to change, but no big deal. ill just play some games right now i thought to myself.
i fired up street fighter 3, worked great. i played some tekken 2, no problems. i started browsing through my list of games and i then chose to play some smash tv. (the pc has been on for a good 30 min), i press start, and all of sudden i detect a distinct burning smell. i stopped immediately and went to look at the pc, but i didnt see any smoke or anything, but in fear i just turned the pc off completely. the smell was pretty bad and smell kinda like rubber, but of a more computery type rubber if ya know what i mean.

i didnt have time to look at it, but im wondering if anyone can give me some tips as to what to check first?
im hoping its just dust buildup in the power supply or something and i can just clean that out and be good as new. of course it may be an actual part, but my question is, why would it just start burning all of a sudden like that? its fine one minute, and then probably in about 5 seconds of starting up smash tv i smell the burning. my pc is open, so i guess it could be wiring getting caught or something. any suggestions?