We've got a farm of Citrix Presentation Server 4.0 running on W2K3 EE no SP. After a power crash, seems that several ntuser.dat files in the user's roaming profiles (stored on NAS) have become corrupt (I've used regrecover to show that the subkeys on the user hives are scrambled, only a few still readable). We've observed that in many ocassions, when the user attempts to log into the server, the server becomes unresponsive. No further RDP/ICA or RPC exec connections can be made, but it responds to ping and you can still browse the c$ share on it. A brief kernel dump analysis shows registry resource contention (winlogon0, but no sub-process information). I was wondering if anybody came accross this before and if there is a way to determine which process is causing the server to freeze.