PS C:\Users\qn> cmd /C echo 1234 | runas /user:surf "C:\Program Files (x86)\Mozilla Firefox\firefox.exe"
Enter the password for surf:  <<<-------- no prompt but does NOT work -------->>>
Attempting to start C:\Program Files (x86)\Mozilla Firefox\firefox.exe as user "QN-SL510\surf" ...
RUNAS ERROR: Unable to run - C:\Program Files (x86)\Mozilla Firefox\firefox.exe
1326: Logon failure: unknown user name or bad password.
 PS C:\Users\qn> runas /user:surf "C:\Program Files (x86)\Mozilla Firefox\firefox.exe"
Enter the password for surf:
Attempting to start C:\Program Files (x86)\Mozilla Firefox\firefox.exe as user "QN-SL510\surf" ...
PS C:\Users\qn> <<<-------- works -------->>>