|Defragment the drive from which files are being copied.|
Check that the USB port you're using is actually USB 2.0 and not the slower USB 1.1
Look in Device Manager. At least one of the USB hubs should be labelled "Enhanced" (this means USB 2.0). Hubs which are not labelled "Enhanced" are the slower USB1.1 type.
The remedy is to buy and fit a USB 2.0 expansion-card which fits into a PCI slot.