Thank you Lonkero for your support but I am still encountering a strange problem.
Entering the new screen saver file name into: HKEY_CURRENT_USER\Control Panel\Desktop
SCRNSAVE.EXE working fine but the problem is with entering the waiting time “ScreenSaveTimeOut” because the new value (e.i 180) entered to this key appeared to me when I check regedit but does not act.

For example I entered 180 to this key but I found that the BC waiting only 60 seconds then activate the screen saver.

In the screen saver GUI I found that selected screen saver & time out (1 minute) are not active (gray).

Why it insist to make the time out value 1 minute although I have changed it? Thank you.