limiting windows user accounts

Hello

I’ve set up a limited user account in windows XP with broadband password already saved in the connection software.

Is it possible to time-limit the account so that people can only log on at specified times (eg. 9am – 5pm) ?

And am I correct in assuming that user with other logon ID’s who have access to this account will not be able to copy the broadband logon password from the connection settings?

All I’m trying to do is make the internet available at certain times without having to dislose the broadband logon password on a home pc.

Thanks in advance.