Resolved! This was not anything to do with Dexpot itself. Other standard account errors came to light and re-creating the user profiles immediately resolved the Dexpot problem (and all the other applications issues).

I've just installed Dexpot on Win7 Home Premium. My Admin user can start and run it without any issues but my standard users cannot get Dexpot to run at all, nor does it show in their Start/Menus. For them the splash screen comes up, no taskbar icon shows and that's it! Dexpot shows as a process in Win 7 Task Manager, running under UAC Virtualisation. (Same as the Admin account). I've tried regsvr32 %windir%\System32\mscomctl.ocx with no effect. Any ideas please?