I am experiencing a similar problem and at least in one case no AMD is involved.
In Windows Explorer if I select too many files and press Ctrl-C or right click to Properties, explorer.exe crashes and ntdll.dll seems involved in that.
The problem is affecting a Compaq Computer with Pentium CPU and Win XP SP2, a DELL Laptop with Win XP SP2 and my home computer (no brand name at hand) with Win2000 SP4.
I have tried the solutions suggested here but they did not work.
What I found particularly annoying is that this problem is quite common, but Windows is totally absconding.
Their support page mention the problem and a hotfix for it:
http://support.microsoft.com/kb/824136/
unfortunately the hotfix is not available for download.