A. There is no NT speaker driver like there was in DOS, however this used to hammer performance and it is better to buy a cheap soundcard.
The very nature of this driver prohibits its use. A preemptive multitasking operating system will not allow enough CPU cycles to generate the sound. The sound is generated by pulse with modulation which requires 100% of CPU time while the sound is being played. Sound cards offload this to their DAC chips