dell 5150

Pleasant day. I have a dell 5150 laptop that i had a administrator password on. I had sent it to upgrade on couple software. When i went to collect it they showed me that it worked fine. However, few days later i tried to turn on the computer and my administrator password does not work. I went in search for the technician but can’t find him. Can anyone help me get into my laptop please? I have a lot of important information stored.