After installing .NET 3.0 on one of my test servers, I could no longer connect over RDP. From the client, the connection would just terminate with no errors. After looking at the Windows Event Log on the server, I found:
Event ID: 26
Application popup: : \SystemRoot\System32\RDPDD.dll failed to load
After looking around, this appears to be an issue with the installed nVidia driver, though ATI users have experienced this as well. Adding the following registry value and rebooting, I was able to RDP again.
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management]
Just going to make this short and simple, there are many places, including Microsoft documentation, which state you can set the event log size up to 4GB. While this is true, it will never get remotely close to reaching that size, or 1GB even. Due to some very bad design, the event log uses memory mapped files under the services.exe process, which due to another very bad design, is limited to 1GB pool.
This apparently is not an issue in 2003 64bit, and is resolved in 2008.