PsTools to the rescue
We were having memory issues on one of our production servers today, no one was able to get in via Remote Desktop or any other remote access tools. PsTools by Mark Russinovich was a life saver, it allowed me to query the processes running on the remote machine and also their memory usage, we were able to diagnose the issue and fix it quickly once we knew what the cause was. The tool suite also has a bunch of other useful tools that work on remote boxes as well.