Remote Desktop lets you control another computer across the network. To use it, first enable Remote Desktop on the computer you want to control. Then, follow these steps to connect to it:

1. Click Start, type remote, and then click Remote Desktop Connection.

2. In the Remote Desktop Connection window, type the name of the computer you want to connect to. You can configure the display size and settings by clicking the Options button.
3. Click Connect.

The Remote Desktop window will open and show you the remote computer (assuming nobody is using it–only one person can use the computer at a time).

If both the client computer and the remote computer support Aero, you can use Aero within Remote Desktop. This works even if the client computer has Aero disabled, so long as the computer supports it.

If Remote Desktop doesn’t connect, it’s probably a firewall problem. When you enable Remote Desktop on the computer you want to control, Vista automatically creates the necessary firewall exception. So, it’s probably a network firewall such as a router. I can’t give you specific instructions to fix this, because every router is different. However, you will need to open TCP port 3389. If you are using Network Address Translation (NAT), you will need to forward traffic for TCP port 3389 to your Remote Desktop host’s IP address.