Up until now, I've resisted the temptation to get drawn into this thread, 
but the plethora of misinformation makes it impossible for me to keep quiet 
any longer....
  Calling Int 19h to reboot a PC is unreliable!
  The function of Int 19h is to invoke the bootstrap loader - period. What it 
specifically does *not* do is reset the interrupt vectors or reinitialize the 
memory manager.
  It may or may not work on specific machines or in specific operating 
environments, but will definitely *not* work in all cases (at least not 
without some shielding code!) In the (good?) old days of 16-bit real mode 
environments, the only reliable way to reboot was to call FFFF:0000. 
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