internet based problem..plz help

i stay in hyderabad and i have BSNL broadband connection.. recently i asked my cousin to format my system becoz it was very slow....
now its quite fast...
but the prob;lem is iam not able to open any of my mails.ihaven't downloaded yahoo messanger and gtalk....yet
but when i try to open yahoomail/gmail/orkut..in IE i get 'the page cannot be displayed'
iam able browse in google but not able to open my mails.....


plzz help me .........