MY COMPUTER HAS BEEN LOCKED

Question

HI MY NAME IS DONNA I REALLY NEED YOUR HELP MY COMPUTER WAS ON SCREEN SAVER I CAME OUT OF SCREEN SAVER AND IT TURNED BLACK, THEN I PRESSED Ctrl, ALT, DELETE, THEN IT CAME UP THIS COMPUTER IS IN USE AND HAS BEEN LOCKED. ONLYCPQ21456269912/DONNA OR AN ADMINISTRATOR CAN UNLOCK THIS COMPUTER! MY MOTHER GAVE ME THIS COMPUTER IT WAS HERS IT IS A PRESARIO 6OOO COMPAQ,I REALLY NEED YOUR HELP SO I CAN DO MY WORK FOR SCHOOL DO YOU THINK YOU CAN HELP ME.