>hi all,
>I'd like to plan the setting of a PC to become a Remote Access Server during the night and to stop it during the day.
>How can I do?

There are any number of ways; products like PCAnyWhere or the freeware VNC product could do this; if you need to use it as a RAS-style server, there are native tools in Win9x to do this, and you have RAS available as a service in NT/2K/XP.

Win2K and WinXP have Terminal Server and Remote Desktop Connection capabilities which can be enabled and accessed via the TSAC or RDP protocols. You can also use NetMeeting, or use MS Messenger to share a desktop or an app to a remote client also using the product.