explorer.exe runs at 100%

Ok, it actually runs at 50%, but I have a dual core, so it is 100% of one core. I have used Process Explorer from SysInternals to find out which thread (and it's call stack) is eating up all the CPU. What I have found is the ntdll.dll is using all the CPU and here is the call stack:

msvcrt.dll!wcschr+0xe
ntlanman.dll!NPOpenEnum+0x23d7
ntlanman.dll!NPOpenEnum+0xe8
MPR.dll!WNetPasswordChangeNotify+0x90b
MPR.dll!WNetLogonNotify+0x104b
MPR.dll!WNetPasswordChangeNotify+0x933
MPR.dll!WNetLogonNotify+0x1129
MPR.dll!WNetLogonNotify+0x10d5
MPR.dll!WNetCloseEnum+0x1d80
fdWNet.dll!DllUnregisterServer+0x1bcb
fdWNet.dll!DllUnregisterServer+0x21f2
ntdll.dll!TpCallbackMayRunLong+0x32b
ntdll.dll!RtlRealSuccessor+0x136
kernel32.dll!BaseThreadInitThunk+0xd
ntdll.dll!RtlUserThreadStart+0x21

I have wiped my machine 100% clean and reinstalled fresh, slowly over about a two week period, the problem is back. I don't have a clue why. Any thoughts on how to track this down?

What do you mean by "make a clean boot"? Do you mean reinstall the whole machine AGAIN? This is not my personal computer, it is my work computer. The IT department does the initial install because they HAVE to put this HD encryption software on the machine. It turns out that this last install was the first time I got this encryption software on my laptop. Mind you, this 100% CPU issue happened on the old install, too, so the encryption software is NOT the cause of the problem.

But what this HD encryption does mean is that I cannot do some things others can do, like boot off a CD and read my hard drive. I have to boot the OS as is, no if's and's or but's!