Since most dialup is done from laptops which are easy to steal, it is very insecure to save passwords for dialup connections. The option can be deleted from NT by adding a REG_DWORD value of DisableSavePassword = 1 to \\HKEY_LOCAL_MACHINE\CurrentControlSet\Services\RasMan\Parameters
Dialup Networking will no longer display the Save Password checkbox and it will forget all the password it had been told to remember. After verifying the correct operation, update your Emergency Repair disk by running rdisk.exe