I've confirmed this list of systems using ATI graphics cards where the target ring does (and does not) work on.
It WORKS on:
Windows98 with Radeon 7200
Windows98 with Radeon 9800 Pro
WindowsME with Radeon 8500
WindowsME with Radeon 9800 Pro
It does NOT work on:
WindowsXP with Radeon 9200
WindowsXP with Radeon 9000 series for Laptops
The problem may platform specific (XP Vs. 98-ME) for ATI users at least. The only time I've seen the target ring fail on Windows98 was with an old ATI 128 Pro with 32mb video ram.
If anyone has seen the target rings work on an ATI card using WindowsXP, please post here