I run two accounts on one computer. COH stores all the client settings in the same registry key, even if you have multiple installations. Annoying! (I also kept force-ejecting my main account from the server because I'd start the other client, and the username would be there in the box, and I'd put in the password, and boom, now I have NO clients running... thanks for THAT UI mechanic!

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I had been starting one client, changing the account name, logging on, changing window position, window size, gamma, sound volume, and a half dozen other things, log the other one on, repeat.
However, I do it in one click now. (Stop here if you don't want to mangle your registry- if you don't know what you're doing you will definitely kill your entire windoze install, a meteor will crush your house, etc etc. If you really want to set this up but are unsure what the reg.exe command does, get a friend to help you.)
Here's how to set it up:
- Shut down COH. Every copy. (Addict!)
- Open one COH client, set it up the way you like it for that account. Shut down COH.
- Open the Registry Editor (start-run-regedit). Go to HKEY_CURRENT_User\Software\Cryptic
- Right-click the "Coh" key and choose Export
- Save this file in your COH directory as set1.reg
- Launch COH for your other account, get it all set up the way you like it, close COH, open the registry editor, go to the same key, export it again, and save it as set2.reg
- Now right-click both .reg files and Edit them with notepad. Remove every line you don't want getting reset with every launch. In particular, remove the CurrentVersion line (so COH doesn't break next time there's a patch), and the Auth line (so COH doesn't break next time they change the IP of the auth server). I also removed Majorpatchwebpage, webpage, dbserver, transferrate, and locale. Remove anything that you want the game to "remember" when you change the setting in-game. Save the file. Do the same for the other .reg file.
Make sure you have reg.exe (I think XP comes with it; if not you can get it from Microsoft on the technet site.) Open a command prompt (start->run->cmd) and type "reg /?". If it says "command not found, you need to go get reg.exe and drop it in your windows folder.
Now make two .bat files to start COH. My account1.bat looks like so:
---
@echo off
d:
cd d:\program files\city of heroes
echo Importing settings for ACCOUNT 1...
reg import set1.reg
CohUpdater.exe -renderthread 1
---
account2.bat:
---
@echo off
d:
cd d:\program files\city of heroes
echo Importing settings for ACCOUNT 2...
reg import set2.reg
CohUpdater.exe -renderthread 1
---
Make a desktop shortcut to both of the batchfiles and you're in business- one-click COH settings.
As a recap, you have SIX new files for 2 accounts: 2 .reg files in your COH folder, 2 .bat files in your COH folder, and 2 desktop shortcuts. You may have also added reg.exe (from Microsoft) to your windows folder or your COH folder (anywhere in the PATH will work).
As a side note, you must actually launch one and get into the game before launching the second- or the second account's batchfile will overwrite the first account's registry entries, and you'll get two COH windows with the same settings. (Not a problem, but kind of ruins the purpose of doing this.

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