there was something happened with my laptop

Yesterday, after having 'sahur' i wanna to surf the internet so i attached my laptop to my broadband. Then my dear lappy updated the avast. huhu suddenly the siren made a loudly sound. Avast detected viruses without stopping so i unplugged the broadband and turn off lappy. After a while i try to on lappy but i couldn't get into the interface of windows. i tried, tried and tried but to no avail, i still couldn't get into. what happened to my lappy?? can u all tell me what happened to lappy?

p/s: curently using a computer at post grad's room.