Check your DMA settings:
Go to Device Manager/IDE ATA/ATAPI Controllers - right click and select proerties/Advanced Settings.
If Transfer Mode is set to "PIO Only", change it to "DMA if Available". Then re-boot your machine and check your settings again.
If XP hasn't captured your new settings, you may need to uninstall the IDE Controller and let XP find it on re-boot automatically. There is a bug in XP and this often causes probs, most often after a system freeze or a crash.