I recently bought a SATA USB 2.0 external drive case and a IDE USB 2.0 external hard drive case, on Ebay. Neither cost more than about £11. As it turned out, both were externally identical.
I attached a SATA drive (formatted in NTFS) to the SATA drive case electronics, connected it via the supplied USB cable to a computer running Windows XP, and it worked without any adjustment.
I tried several small old IDE drives in the other box and none of them worked. None of them showed up in Windows Explorer, or in the control panel’s disk management, though the USB device showed up as a disk device in the Control Panel Hardware. I Googled for a solution to this, and found that it was a recognised problem, but no clear solution was offered.
It’s therefore worth detailing what I did next. I took an 80GB NTFS formatted hard drive out of an old PC I’d been using as a backup device, and tried to find a jumper to put on it to set it to Master. I couldn’t find a jumper, so connected it up anyway to the IDE external box electronics and plugged the USB cable into a PC running Windows XP.  It worked immediately, and I was able to read the contents in Windows Explorer.
It looks like the previous format of the hard disk is important.