''Pseudo-syntax, not exact instructions.. If IsHardwareIdValid() == True Then ''Let the code run ''here Else ErrorMessage() End If in asm: mov eax, IsHardwareIdValid() cmp eax, 0 jg validID ''else, falls through to error message ErrorMessage() exit() :validID ...good code.. ^^change jg to jle (or jz maybe?). Then it will jump to the "good code" when the ID is invalid : D -reversing the logic of the original if statement/control structure.