i don't konw if my computer is hacked by someone or not

i try to access into my windows...
screen shows that I should choose one of the
owner and guest to get in....
but both of them are not functioned well.
when i click either of them..the computer load
for a short while...but the screen remain unchanged.
several seconds later..it asks me to choose
users again....
i can't get into my computer...

has my computer been hacked by others ?
or does it get virus?

can anybody tell me how to deal with this issue plz?
thank you