Since almost no one else seems to have this problem I would hazzard to guess its the machine its on has a problem rather than mirc, its likely that mirc is doing something that causes some part of a device driver of a piece of hardware to be set off that is either buggy code or the device locks up. It just happens to be mirc that does this, you might run 1000 programs and only mirc makes this happen and you might run 2 and they both do it.
