access denied

something i did to my computer has made it so access is denied to my c drive and program files. all of a sudden my c drive is full and access is denied . system restore denied dont have permission, malwarebites wont ope access denied. i still show all my files ar in computer i just cant get to them. Any suggestions?

Can you get to the Control Panel and create a new user?

Do you remember what you did to cause this?

Could it be malware?