Lost access to target machine

Installed TeamViewer; Gained access to target machine 1 time;  Received a message that I needed to restart my machine;  Restarted machine;  Cannot log into target machine - "invalid password";  un-installed TeamViewer; Re-installed TeamViewer; Same result - cannot log into target machine - "invalid password"     ----  Others can log into target machine using ID and password --  Suggestions as to what is wrong  and how to fix it????  Thanks.