Remote Desktop permits remote access to a machine with there is no requirement of person at other end. Remote Desktop uses an account the pre exists with a user name and password and is set up in the list of Remote Desktop users. When trying a remote connection in this method, you should know the IP address or if on a local area network; you should know the computers name and password. It works only the Windows XP Professional, Vista Business, Vista Ultimate version
Remote Assistance permits remote access to a system but in this method both users must be available. If Remote Assistance is required on one end, the user sends an invitation to connect through instant message or e-mail. It works for all versions of XP and Vista.