If there is a video of people talking about me in a negative fashion, can I take it down?

You do not say where the video is located. If it is on YouTube, this is what to do: Join Youtube. Sign into your account. Go to the video. Below the Video is a little flag button. Click that flag button. A drop-down menu appears. Click "Infringes My Rights." Then select "Invades My Privacy." This will take you to a page that gives instructions. File a report and state that this identifies you, you are identifiable, and the people are saying defamatory things about you that damage your safety and reputation. The series of questions ask if you are comfortable contacting the people on your own. You should choose "No," because obviously you are not. Follow through and fill out the forms correctly. Emphasize that this names you, that it identifies you, that it harms and endangers you. It may also be Defamation. Defamation claims are very hard to win in court. If you wish to do this, contact a lawyer. It is a sort of lawsuit that can cost a great deal of money to pursue and has a very high chance of not succeeding. If the video is on youtube and has been embedded elsewhere, having it taken down off youtube will remove it from the other locations, too. If the video is hosted someplace other than youtube, that place should also has similar flagging instructions. If all of this does not get this off the internet, speak with a lawyer as fast as you can. If you are being harassed by these people or others online, file a complaint with the Internet Crime Complaint Center, which is an FBI clearing house for internet complaints. That is www.icg.gov.