Yes, Dark Age of Camelot can be played in a window.  To activate windowed mode you will need to first log into the game cleint. Do not use the Quick Entry option, as you will need to activate this feature from the Options menu located at the Character Selection Screen.

Choose your server
Click Options
Click Enable Windowed Mode
Click Accept

Please take note of the message that is displayed at this time:

This feature will not work on many systems. It could result in system crashes, low frame rates and other problems. If you enable windowed mode and it doesn't work correctly, you must return to normal mode before calling customer support.

Click Options
Uncheck Enable Windowed Mode
Click Accept

You need to restart Dark Age of Camelot after this setting change in order to play in windowed mode from now on.

Please keep in mind that this may significantly decrease game performance and should be the very first feature disabled whenever troubleshooting a technical issue. Mythic Entertainment will not assist in troubleshooting technical issues with players until this feature is disabled.