{ MARCO MILTENBURG >> if you find SOURCE to detect/give up time slices For Windows/OS/2/Desqview, >> could you post it? I have stuff For Desqview, I believe. > Procedure GiveTimeSlice; Inline( $cd/$28 ); This is nice, but you have to be sure that you have enough stack space left, because Dos or TSR's that hook this interrupt will use SS:SP For their own stack. I use the following in my multitasker detect Unit : } Procedure TimeSlice; Var Regs : Registers; begin Case OS_Type Of _Dos : begin end; _DV, _DVX : begin Regs.AX := $1000; Intr($15, Regs); end; _OS2, _WINS, _WIN3: begin Regs.AX := $1680; Intr($2F, Regs); end; end; end;