hey guys i have a problem with my pc when i started my pc then it asks for the password, but actualy i had not set any username and password, i think this is a virus problem, and bcoz of this i cannot enter to the pc. no one is using this pc accept me, plz help me its urgent

waht p-ass word for bios or operating system? for bios remove the bios battery and turn on your computer turn it off and then attach the bios battery then set your your bios again because it will returns to default.
If your operating system is locked then try to use password breaker try in the internet where you can find it.

have you update your windows using windows update recently?