i have seen the bluescreen by default on both xp home and xp pro editions. but i know for certain it isnt caused by nukes and the such.

how long does it take for your computer to reboot?
does it happen only when you open mirc? try and boot in safe mode.

i use a very good antivirus called avast. along with an online scanner. Avast.com its one of the viruses scanners listed in one of the stickys.