Maybe a fresh face will be able to see the problem. I have some protected mode code that calls a software interrupt. No problem, it enters the handler just fine. In the midst of that handler, it calls itself as an interrupt, but with a different parameter to execute a different subset. Problem is, when it makes that second interrupt call, the machine ends up rebooting. Anyone know why this would be happening? Stack is okay, I checked that. On top of that, the interrupt handler was just called, so I know the IDT entry is kosher. Ideas?