Check the following thread for a work-around for Win 7 64-bit NVidia issues:
http://displaylink.org/forum/showthread.php?t=146
1) disable the nvidia display driver in Services (startup manual)
2) edit the registry to TdrLevel 0 (google for details)
This does result in a bad wake from display off/sleep - but that is solved by hitting ctrl-alt-del, then click cancel.
(I just disabled the services and things worked for a while. I'm back here searching the forum because I'm having issues after moving my PC [first reboot in a long time].)