You used the filter option in contents summary or mediacenter. You will see the information "Filter: Yes" next to the filter options. To unset this filter just click on "Set" without a chosen option. The filter will be unset.

Please go to Admincenter. Choose the menu Security.

You will see a complete list of all users. Just click on the people button in actions to edit this users profile.

To edit your own user profile please click on your username in the top right of the Admincenter page or in menu Home -> My profile.