There are five identical computers on this network, and they happen to be the only five in the network running Vista. All are used via remote desktop by users not local to the network. All use similar, if not identical, software. All use Trend Micro Worry Free for antivirus. For the past week, three of the users have experienced random problems accessing network resources. The cursor will just spin, sometimes if you wait five or ten minutes the resource will finally come up, sometimes everything will lock up (mouse still moves but you can't do anything), and sometimes it'll go to a black screen with an error "Logon Process has failed to create the security options dialog. Failure: Security Options." Two of these computers have had no problems whatsoever. One had a couple problems at the beginning of last week, but nothing since. Two have had continuing - but not constant - problems. I've googled the error and there are many references to problems with antivirus and antispyware programs, but all five of these are running exactly the same version of Trend Micro and nothing else. I did a system restore on the two computers with the most problems back a week and a half before any problems were occurring and turned off automatic updates, but that didn't help. The event logs are no help at all. These machines have been in production for over a year with no issues. I am just at a loss as to why only a couple of these machines are having problems, or what's causing them. I should also say that the same issues can occur when the remote desktop is from within the same local network. I have not had the chance to work locally on any of the machines -- with no remote desktop at all - long enough to see if the problem exists, but I believe it would. There doesn't seem to be anything about this issue that points to remote desktop as the issue. Any help would be very much appreciated!