TRIAL PERIOD

I installed an AUTOCAD program 2 yrs ago and had no problems. Bought a used pc and installed pgm on it. Hit the shortcut on my desktop and a message came up “sorry trial period has expired.” This sounds like a reference is being made to a demo ofsome kind. Have no idea what was on this pc before I purchased it. Uninstalled the program and went to win.ini file and deleted the one instance of ACAD and reinstalled AUTOCAD. Tried to bring it up again and received the same message. Any help?