

Go to the line from where you want to select all the lines below, you can try using Ctrl+G and adding the line number if you know it,.Now keep holding Shift and press Page Up button.Now press Shift, and while holding press End, you should see the first line being selected,.Go to the line number from where you want to select all lines above, keep the cursor at the start of the line (press home if the line is too big to get to the start),.

If you have a huge file and you just want to select all the line above or below a specific line then you can do so by following the below steps, Notepad++ select all above: I usually use Notepad++ to work with large files and it is really useful as its undoubtedly the most powerful text editing tool on Windows OS.
