I checked everything as per the procedure of login through windows with networking mode ( as suggested in earlier thread), and found currentVersion\Winlogon where both values of Shell ="explorer.exe" and
Userinit= "../System32/Userinit.exe," as it is. Hence nothing resolved.
Althought a temporary Sol that I found was that after normal booting for my windows 7 ultimate version, is to open "windows task manager"( by Ctrl+All+Delete) and in process pane right click "explorer.exe" and select "end this process".
Afterward while I am again calling the "explorer.exe" through task manager>file option>New task(run...) Windows is resuming as normal.!!
But the problem is that after restart, again I have repeat the same procedure (kill and call for explorer.exe) explicitly in the same manner.
Please suggest some permanent solution.