I ran the following command on the windows command prompt
C:>tasklist /fi \"Imagename eq BitTorrent.exe\"
The output of which is
the easiest way is with using WMIC:
c:\>wmic process where caption="BitTorrent.exe" get ProcessId
EDIT: As the WMIC is not part of home editions of windows:
for /f "tokens=1,2 delims= " %A in ('tasklist /fi ^"Imagename eq cmd.exe^" ^| find ^"cmd^"') do echo %B
Here is used CMD of the caption.You can change it in the find and tasklist parameters.
If this used in batch file you'll need %%B and %%A