Did you clean out your temp files?
Download install and update CcleanerAttention : the installation package comes with the Yahoo toolbar
if you do not want that you have to, untick the box accepting it during installation process.After installing and updating go to options - advanced and tick prompt for registry back ups
Now Start up in safe mode
Do two runs
1) Click on problems and tick all. Click on analyse. At the end you will be prompted for storing a backup.
This will be stored, as a default, in My documents.
2) Click on cleaner click on analyse and accept all files to be removed.
Most Internet connectivity problems arise out of corrupt Winsock settings due to the installation of a networking software or Malware infestation.
If your using Windows XP SP2, log on as an administrator.
Go to Start > Run and type: cmd
Press OK or Hit ENTER.
A dos Window will appear. Type or copy/paste the following: netsh winsock reset
When the program is finished, you will receive the message: "Successfully reset the Winsock Catalog. You must restart the machine in order to complete the reset."
Close the command box and reboot your computer.