If you install Remote Desktop Web Connection in Windows XP, a user on another computer can use Start / Programs / Accessories / Communications / Remote Desktop Connection to begin the process of connecting to your computer.
The default color depth of this connection is 256.
Before a client connects to your computer, use Group Policy to set the maximum color depth you allow, a value that should NOT exceed the capability of your video adapter:
1. Start / Run / gpedit.msc / OK.
2. Computer Configuration / Administrative Templates / Windows Components / Terminal Services.
3. Double-click Limit Maximum Color Depth, enable the policy, and set the maximum color depth.
4. Press Apply and OK.
When the client wishes to connect, they:
1. Start / Programs / Accessories / Communications / Remote Desktop Connection.
2. Type the name of your computer.
3. Press the the Options button.
4. Select the Display tab.
5. Select the color resolution they desire.
6. Press Connect.