INT 2F U - Microsoft Profiler (PROF.COM/VPROD.386) - STOP PROFILING
        AX = 4504h
Notes:  profiling is also turned off by the key combination
          LeftShift + RightShift
        for PROF.COM, this programs the CMOS clock by reading register 0Ch
          and clearing bit 6 of register 0Bh.  It then masks IRQ8.
SeeAlso: AX=4505h,AX=4506h,AX=4507h