although the black dos screen opens up, it quickly closes again,
I'm not sure but it sounds like you might be typing the commands into the wrong place. You need to open the command prompt first and then type commands at the C:\> prompt. Try this:
Press and hold the Windows key then press the R and then release both keys.
Type cmd into the text box.
This will open up the ms-dos window, command prompt window, dos window, black screen - call it what you will. Now you can type netstat commands and the screen will stay open.