Re Open Office, could you please give some more information such as steps to reproduce or error messages or what is happening.

Re NVDA, when you run the downloaded file, you have the option to continue running or install.  If you install it, then you should be able to start it either from the start menu or with CONTROL+ALT+N.  Once it is running, it will appear in your system tray.  The icon in 2017.3 is a purple square with a white stylised "N" inside.  By default it should start speaking as you perform actions on the computer - visually the screen won't look any different.  If you have turned speech off or have a problem with the synthesizer you are using, you might not get speech, but if that's the case, let me know and we can try and troubleshoot a bit closer.

Kind regards

Quentin.