Originally Posted by jc105
Assuming they are XP pro...
Right click 'My Computer' choose properties, choose the remote tab in the window that opens. Make sure the second check box, "Allow users to remotely control", or something to that effect.
That should be done on the machine you want to connect to(Server). On the client computer, click Start -> Run -> type 'mstsc' (No quotes) then hit enter. Find the IP of the server computer, assume you know enough to get that info. Enter that into the window the appeared. Press enter.
YOU NEED A USERNAME THAT HAS A PASSWORD TO REMOTELY CONTROL A PC.
Otherwise screw all this and install realvnc (google search) on both pc's and the setup is simple for vnc, and well documented.