Can system restore help (and/or be reached)? I'm no computer geek, but wonder whether a reset to earlier configuration, then delete the Google browser altogether might do the trick. If Google were wanted as a back-up presumably it could be re-installed without making it the default?

Someone with proper ideas will doubtless be along soon, good luck.

PS: I wouldn't fiddle with the boot order without expert guidance, the above looks OK as to 1 and 3. As long as there isn't anything in either drive they will simply be ignored. 2 I am less sure of, but as long as you've changed nothing I would leave it as is for now.