Setting up a remote connection doesn't need any special software or application to be installed. For windows XP computers or Vista Home edition, it is a simple setting that can be checked or unchecked. If remote PC access is allowed, then a remote admin can log in to a computer in another location and use the remote desktop. A Microsoft computer can even provide a Mac remote access. This article provides a guide to using a remote desktop connection.
To set up a computer to allow remote connections, go to the Control Panel and click on 'System'. Go to the 'Remote' tab and check 'Allow users to connect remotely'. That's all that it takes. Also, assuming that the computer is connected to a network, other users will be able to log in to this desktop remotely. When someone logs in remotely, the local desktop on location is automatically locked so that no one can run applications or get access to files locally. Note, however, that multiple remote connections can function simultaneously on the same computer. They can each run their own applications, and their sessions will be preserved separately.
Obviously, the remote PC connection needs to be secure and only selected users can access a remote desktop. To enable this feature on a computer, one needs to be an administrator or a member of the 'Administrators' group. To get access to a remote computer, one must log in as an administrator or a member of the 'Remote Desktop Users' group.
Remote Assistance is a specific type of remote PC access. The one providing the assistance gets to see the remote desktop and chat with the one using it locally as well as provide any help required. If permitted, the remote helper can also operate programs on the remote computer as part of the assistance provided.
Apart from the basic in-built functionality that enables remote connections, there are other options for advanced users or enterprise level users. There are plenty of third-party tools and software that can enhance the remote desktop functionality and add more security features. Wikipedia has a huge list of all the available remote desktop software, both paid and free, and for the PC as well as for Mac remote access. The list includes everything from the famous WebEx and UltraVNC client and server to Symantec's pcAnywhere.