Populate textboxes in listview based on value of dropdown without postback

Hello All,

I am in dire need of help. I have a listview with a dropdown and 3 textboxes associated with it.I have 2 such combinations in the same listview. On dropdown selection, the 3 textboxes need to be populated based on the value selected from the dropdown. So my SQL statement, looks in the database for corresponding values for the item selected from the dropdown.Now, I need to insert all these values(dropdown, 3 textboxes) in the database.
Everything is working fine, but with postbacks. This is the first time, I am making a web-application and I understand that the page refresh on each dropdown selection is not acceptable.
I tried using ajax update panel. worked on it on and off for a couple of months, but just couldn't get it to work.

Help Puhleeeez!!!!!!!!!!!!