For the problem i faced, i tried all options as suggested here for similar probs, DNS flushing also, finally i had stopped Avast and my Browser started workign fine but then my net security was stopped which was again a serious matter.
I tried to restart avast but it could not dont know what resons must have been. Finally i though of uninstalling Avast and then will resinstall. In the process , option was offered for Removing the Software, Updating, Repairing. First i tried repairing, n then i went to ms config, enabled all software during startup, but then i noticed Avast when ticked it did not get selected . Finally i reestarted , again went to SOoftware Install/Unistall, there after selecting Avast i press for option Update , and it started updating. This seemed that Avast has started working 'cause earlier even i opened Avast and pressed for the Program to Start, it did not.
Now it updated , and alhamdualillah it started . Avast WEBSHILED which earlier was creating problem with net connection n browser connectivity also started working.
All started working fine. I rechecked, with Google chrome, and IE7 , all opended and could surf net and Avast all features working ok + can update to latest virus ....