Car won't start

My car doesn't start either and I know it is the starter. When someone hit the starter from under the car and it started as I turned the key. So I need a new starter but can I jst buy the part and get a friend to put it in?

The buzz could be the solonoid trying to engage. Generally it is a clicking sound. A buzz sound towards the back is usually the fuel pump running. Try beating on the starter with a hammer or wrench. Sometimes the solonoid sticks and this will free the contacts to allow them to reengage and start. To answeer the other questions abour having a friend install a starter. Yes you can have anone you trust that has ssome mechanical ability install your starter. It is a pretty simple task. Good luck.