Quickest, easiest, best solution for this may well be, Save data you want & do a re-install. Since you can't Restore, Repair like would bring back such basics. I'd be curious what security you were using. IF you rebuild, use MSE, henceforth.
Sounds like it's timely, anyway, to fix the mess you say you've made over the past 2 wks or so. Probably best overall, in the long run to start fresh, anyway.
Keep posted.
Cheers,
Drew