[quote="JSWP"]1. On booting it will not start at the default page but insists an starting from the STARTUP folder.
2. If I set it to not display the lister on boot it does the same as 1.[/quote]
Try turning off Explorer Replacement (Preferences / Launching Opus / Explorer Replacement / Don't replace Explorer), then reboot.
If you now get the same folder opening, but in Windows Explorer instead of Opus, it means what you were seeing is something else asking for that folder to be opened, and it was only opening in Opus because Opus was set as the default file manager.
It's usually a misconfigured shortcut in the Start Menu's startup folder (which coincidentally seems to be the folder which is being opened), where the shortcut is pointing to a folder instead of a program.
If the windows are opening without you doing anything, keep Explorer Replacement turned off like above, and see if Windows Explorer windows start opening instead of Opus ones. It's probably not Opus causing them to open, if they are opening by themselves.
[quote]4. The lock up manifests itself by displaying the status bar, such that it sees the files in the directory and sizes etc; but does not list any files.
5. Any attempt to give focus to the window results in a (Not Responding) legend on the windows title bar.[/quote]
We have a guide on tracking down that kind of problem:
Crash, exit or high CPU usage when viewing certain directories
It's usually due to a problems with 3rd party shell extensions or video codecs which are invoked when you view the directory (or specific files, or types of files, in particular directories). It can also be things like virus scanners causing long delays (e.g. if there are huge installers or other large EXE files or archives which the virus scanner decides need deep inspection when Opus tries to do something which should be quick with them). Of course, it can also be a bug in Opus itself (but those are rarer because we tend to find out about them and fix them quickly, and I can't remember the last time we needed to do that).