Does TC2000 have a Advance/Decline Indicator included?. 

I may have deleted the old one about 1 year ago and replaced it with a custom one. When I chose A/D line, it comes up with a custom created indicator that I created which I'm not sure it works. How can I get the old A/D line indicator back.

It may be what you want (I have no idea), but your indicator is calculated for a single stock. Advance Decline lines are normally calculated for multiple stocks.

We have a variety of advance decline lines available. Select Add Plot to Chart (the green plus in the upper left of the chart) and start typing "Advance Decline" (without the quotes). You would then be able to choose the desired Advance Decline line.