I have set one week old threads to be displayed in the forums in my control panel. Before daniweb upgrade, there was a sort function at the end of each forum .. so whenever I had to go farther than one week, I used the sort function. But now its gone, Is there any alternative to it or its there and I cant find it ????

Are you referring to the dropdown that allowed you to Sort By Last Post, Sort By Replies, etc? If so, just click on the little heading within the top of the thread list to sort by that field.

Yes and if I want to display threads more than one week old (I have set my options to show thread only one week older) then what should I do ? Go to control panel or is there something else ?