If you can, try this:
Search for (magnifying glass) and go to
which should open a System Restore window.
Then from the calendar-like interface, choose the first restore point *before* the problem started, i.e. any date that is the first one that has a Restore Point before yesterday, then do the restoring.
(Warning: it may help to first disconnect from the internet, then also disable - temporarily, i.e. turn Off - your anti-virus utility, since they can often interfere with the Restore operation completing successfully.... before doing a System Restore.)
The computer will grind away for a while, then restart automatically, then grind away some more, and hopefully will come up with a message that the Restore operation was fully successful.
And hopefully that will cure the problem.
(PS: Do not choose to do a System Restore if you have recently installed any Microsoft software of any considerable cost. Its installation may be reversed, and you may lose money that way. Let me know if you think that's the case, and I will advise you further as to what to do.)