Battlenet becomes a blank window/lag

I recently built a new PC. All of the parts are compatible and up to date. The first/only game I’ve downloaded is overwatch. When you open overwatch the lag is so horrendous it affects even the menu screen and it won’t speed up at all. It’s a steady lag. On top of this every time I restart my computer I am no longer able to open battlenet. It just becomes a blank window. It fixes it when I uninstall and reinstall but repeats after turning off my PC.

This is a brand new PC the only things I have on it are overwatch battnet and Norton security (they were never an issue on my laptop)

What type of GPU?

That is likely Norton causing the blank screen, very common issue.