Hello, I don’t know much about your battery problems, but for the ADB thing, if I remember well you can :
- Press Shift
- Right-click on the adb folder
- Select ‘Open command prompt here’ (it appears in the menu)
Then it should work. You can then call your device by typing adb devices, and the screen you just posted should appear. Then you can autorise USB debugging from your computer. If it donesn’t work, my bad, 
. You can also make a shortcut on your Desktop and open the command prompt here as you normally would :
In File Explorer, press and hold the Shift key, then right click or press and hold on a folder or drive that you want to open the command prompt at that location for, and click/tap on Open Command Prompt Here option. There is a simplier way I know. Find cmd.exe in start menu and send it to Desktop as shortcut.
The thing with Windows, as it seems, is that you can only execute ADB where the executable is. And then it is much simpler to have the images that you want to flash in the same folder as ADB, so that you don’t have to navigate whithin the prompt to the right place - it’s easy to do with Linux and other UNIX-like, I’m lost with the Windows method.