I’m assuming you’re speaking of DMA mode on your hard drives, since all computers use DMA for other things. To enable DMA mode on your drives, go to the device manager, right click on the drive, properties. In the properties page, under driver I think, there should be a DMA checkbox. Check it, and you’ll have to reboot. If the drives don’t support DMA mode, after rebooting, this box will be unchecked.
I’ve gotten as far as checking the box you suggested, but then a warning window pops up threatening dire consequences if I proceed when my drives aren’t designed to handle DMA, and I’ve been afraid to proceed. I think I’ll try it now.