It is actually easier to do this if you are trying to multibox DDO:
How to Set Up your PC for Multiboxing DDO
If you need to run multiple instances and on the "alt account" you want to lower settings for graphics and turn off sound, etc to improve performance you may note that adjusting the settings in one of the clients affects settings for both or all.
This is because, by default, the game loads the keymap and userpreferences out of your My Documents folder.
To get around that and be able to configure each instance independently of the other, you can create a second user account (or third or fourth....) in Windows (I set mine to Administrator and some cryptic pswd so that game updates can occur without pop-up authorizations.) Then create a shortcut on your desktop like this:
C:\Windows\System32\runas.exe /user:NewWindowsAccountName /savecred "C:\Turbine\Dungeons & Dragons Online - Stormreach\TurbineLauncher.exe"
* Adjust for your path. Mine is in C:\DDO_1. For example:
c:\windows\system32\runas.exe /user:My2Account /savecred "C:\DDO_1\TurbineLauncher.exe"
You will have to set your icon for it, but that is easy as it is in the same folder as the TurbineLauncher.
In the end, you will have 1 regular shortcut and 1+ pre-configured shortcuts that look like the above.
Why Does This Work?
This causes the shortcut to run under the new user you created and will use the keymap and userpreferences from THAT My Documents (location) allowing you to cap the FPS at 25 and lower graphic settings / audio without negatively impacting the game for your primary game session.
As long as you start all the launchers together before logging in to either one, you should have no issues getting them both up and running.
You can also leave the minimized in your system tray.
I've posted this (and the crazy adventures...) of my multiboxing on our guild site for some time. Even got a few others doing it now for fun.
Good luck!
T.