You will notice that with the time change, it will affect how you see post times on the board. Your computer settings, even if correct, will not change how you see them here.

In order to correct how you see the post time, while logged in, go to User CP at the top of the page and click on it. Then go to User Options on the left hand side of the page and click on it. Scroll down the page until you see time settings. You will want to select GMT -5 if you are on Eastern time.