Go to the Control Panel then Network Connections.
Click once on your active Connection.
From the menu on the left, select Repair This Connection.
Also, unplug the modem for a minute, then plug it back in.
Sometimes this allows everything to reset.
If you continue to connectivity problems,WinSock XP Fix
can can cure the problem of lost connections after the removal of Adware components or modifications of the Winsock settings.
Sometimes your Internet connectivity will get corrupted due to invalid or removed registry entries.
Or you can try WinSock2 Fix
, if that fix didn't work.
When you run it, click on ReG-Backup button first to backup the registry, and then click on the Fix button.