Originally Posted by LIGHTNING UK!

Windows XP will often get confused and report that a drive IS running in DMA mode when in reality, it's not. To fix this, Uninstall the IDE/ATA Controller (NOT the Channels!!!) from under the IDE ATA/ATAPI Controllers branch (again in Device Manager) and reboot your PC. Windows will 'find' it again when it boots back up. DMA will be enabled by default.