If the DMA controller really has failed, then no it can't be repaired without a new moterboard - and laptop motherboards are not standard motherboards that you can buy near anywhere - they're specific to the laptop you have.
Before you give up completely
Take out the hard drive and re-insert it a few times (to clean the contacts where it plugs in)
Same with the optical drive, if it's removeable
Reset the BIOS to the default settings.
Ask HP for their opinions
Other than that I can't think of anything you could do - might it be a warranty issue?