Is they're any program that look for update, this could be your problem, or:
Configure the program that automatically checks for updated components or Web pages so that it does not start when Windows XP starts.
Disable Autodial
To disable autodial, follow these steps:
1. Click Start, and then click Control Panel.
2. If you are using Category View, click Network and Internet Connections.
3. Click Network Connections, and then on the Advanced menu, click Dial-up Preferences.
4. Click the Autodial tab.
5. Click to clear the check boxes that are listed under Enable autodial by location.
6. Click to select the Always ask me before autodialing check box (if not already selected).
7. Click to select the Disable autodial while I am logged on check box.
8. Click OK, and then close the Network Connections dialog box.
OR:
1. Start Internet Explorer. On the Tools menu, click Internet Options.
2. Click the Connections tab, and then click Never dial a connection.
3. Click OK.
To set the AutoConnect value in the registry key to 0, follow these steps:
1. Click Start, and then click Run.
2. In the Open box, type regedit, and then press ENTER.
3. Locate and select the following registry key:
HKEY_CURRENT_USER\RemoteAccess\Profile\<ConnectionName>
In the right pane, double-click the AutoConnect value, and then reset the value from 1 to 0.
Jeff