Tax Demand query

All,

  While browsing through income tax site, I found I had outstanding notifications of demand for 3 years ( which I never received ). These are the years when I filed manually. So I guess I need to go to ITO and first get 143(1) to see the reason why there is a demand and then proceed ???

Now few questions:

1)Later when I checked online status of later years, they say no refund-no demand. Is it only for those years. Is there no carry forward system if I did not pay?

2) How difficult is to get it rectified ( I am sure I have filed it correctly ). Is CA help reuired?

What else can be done

Regards

Sree