when i connect my lappy with internet a msg pops-up "Additonal log on information is required " and sometimes when i click a link browser redirects to another page completely different from the former.Anyone having this problem??
That behavior is typical for a trojan, you should check your browser's installed complements, and your pc for virus.
I think your laptop is infected from virus so install trusted anti virus and scan your laptop. and after scanning was complete remove your web browser and reinstall it. its helps you to solve your problem.