cant read mail and can not see many web page

hei
i was instaling the home avast 4
and after that i cant read any maill at my yahoo and hotmail
mor then that i cant see many pages at the web
they jast gone
i have xp profsonal
no ater anti viros(befor the avast 4 i had norton bout it was uninstela)
and i uninstel the avast 4 and it didnt help
hope u can help

Ensure firewall allows access for the Web Shield provider (ashWebSv.exe), it requires internet access.

NAV is notoriously difficult to get rid of:
The tool can be downloaded here: ftp://ftp.symantec.com/misc/consumer/Rnav2003.exe
Manual Removal NAV 2004 - Manual Removal NAV 2004
Manual Removal NAV 2003 or earlier - Manual Removal NAV 2003 or earlier

There are a number of threads with problems installing avast when NAV was previously installed.

Do you use personal firewall? Which one?