"WindowsError: [Error 2] The system cannot find the file specified" is not resolving

"WindowsError: [Error 2] The system cannot find the file specified" is not
resolving

I have created exe file of my python project by py2exe which have number
of files. when i run this exe file in my system. it works fine but if i
put it in another system then it opens login form, then after it doesn't
go to next window which i have written in 2nd python file. it gives me
below error in log file.
Traceback (most recent call last):
File "login.py", line 246, in DataReader
File "subprocess.pyo", line 711, in __init__
File "subprocess.pyo", line 948, in _execute_child
WindowsError: [Error 2] The system cannot find the file specified
I know that it is duplicate question but I have tried many solution of
stackoverflow but i didn't resolve this issue. Somebody help me for
resolving this issue.
And After login successfully it will go to start.py file by this code, But
it is not going and giving above error.
subprocess.call(["python", "./start.py"])
Thanks in advance