Automated Edit:

Dial-Up Modem or PPPoE is Unavailable (Line 87)
http://www.kellys-korner-xp.com/xp_tweaks.htm

To use the Regedit: Save the REG File to your hard disk. Double click it and answer yes to the import prompt. REG files can be viewed in Notepad by right clicking on the file and selecting Edit.

Manual Edit: Go to Start/Run/Regedit and navigate to this key:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\RasMan\PPP\EAP
Delete the sub-keys listed except 13 and 4.

Standard Checkpoints: Go to Start/Administrative Tools/Services. Set these three to "Automatic": Remote Access Connection Manager, Remote Access Auto Connection Manager and Telephony.