I would like to do the following using Group Policy for my XP clients:
2. Disable remote desktop.
1) There is no native GPO policy for controlling USB devices. You have two options. First, you can add in a custom Registry setting to control the Registry value. This can be done with a custom ADM template, or by using the PolicyMaker registry extension. You just need to alter the HKCUSYSTEMCurrentControlSetServicesUSBSTOR Registry key and Start value. Second, you can look at a third party tool such as PolicyMaker Standard, which has a GPO extension that handles devices, including USB drives.
2) Remote Desktop is still referred to as Terminal Services. Therefore, go to Computer Configuration|Administrative Templates|Windows Components|Terminal Services and configure the "Allow users to connect remotely using Terminal Services".