I'm going to need much more information here, such as the version of windows of the computer that is going to connect the VPN and the version of windows on the computer at the other end. Are firewalls being used? If so, what ones? Is SP2 (Windows XP) being used?
I'll give you some basic steps however (for Windows XP) and hopefully this will lead you in the right direction

:
1. Go into Network connections (accessible through the control panel).
2. Select "Create a New Connection".
3. The wizard will appear. Select Next.
4. Select "Connect to the network at my workplace" - you'll notice in the blurb underneath it will mention VPN's. Click Next.
5. Select "Virtual Private Network Connection". Click Next.
6. Give it a name and then click Next.
7. If on dialup or need anything special done before connecting the VPN, this screen is the place to do it. You can specify to use a dialup connection first before connecting the VPN etc. Click Next once finished with this screen.
8. Put in the host name or the IP address of the remote computer to connect to. Click Next.
9. Summary Screen. Click Finish.
If all has gone well, that should be all you need to do. Remember if you are using Windows XP
SP2 then you may need to play with the Windows firewall settings (if turned on) before it will work.
You may also need to setup a user account on the remote computer with required rights/permissions.
If you need any further help, let me know.
Sadan01