I would like to convert DivX encoded videos into its previous form which is mpeg or avi without DivX codec. Can anyone help me?

From the amount of information on Google,I take it you may not have looked any? I can not recommend an exact program. But there sure is alot of information and programs available to do this. I would suggest you read up and download something and try it out.

http://www.afterdawn.com/guides/archive/convert_multiple_formats_to_dvd_dvdsanta.cfm

http://www.afterdawn.com/guides/archive/divx_to_dvdr_with_dvd2svcd_d2sroba.cfm

http://www.afterdawn.com/guides/archive/vso_divxtodvd_2_guide.cfm

http://forums.afterdawn.com/thread_view.cfm/172

Actually I did look but the only thing I typed is "decode divx" and then I got confused so I gave up and went to techspot. Sorry, I dont have time to check links right now I gtg.

That's cool. Just Google the following instead. "convert DivX to mpeg"

DVD ripper is one that comes to mind.