your hosts file might have been modified. check file
Windows 95/98/Me -> c:\windows\hosts
Windows NT/2000/XP Pro -> c:\winnt\system32\drivers\etc\hosts
Windows XP Home -> c:\windows\system32\drivers\etc\hosts
(you can open it by notepad)
remove any line contains 'google'
As a precaution, you should back up the file before modifying it.
