I installed Visual Studio 2015 yesterday. When I opened it it stated that a .dll file missing, so I downloaded that file, and after that it showed a component was missing, so I went to devenv.exe and executed that directly as an administrator and it started up, but Visual Studio still isn't working.
It shows a white colour for most of the screen, including the menu (so I can't get to options to change settings).
Try from your white screen: Press: Alt+T for Tools, then O for Options and untick the following boxes as shown, click OK and reopen Visual Studio.
Useful keyboard navigation from ka_sh's comment:
In case the Options menu is also not visible, then from the General section, press the following keys: 3x Tab, 1x A, 1x Tab, 1x E, 1x Tab, 1x U, and then 1x Enter.