Running 2 copies of Diablo 2 on the same computer
From Diablo Wiki
What I'm trying to describe here is how to have two copies of Diablo 2 running on the same computer without the use of any third party programs. This means that this guide will not provide any information on hacked dll files, or loader programs of any sorts.
To my knowledge, the only way to accomplish this is with the Window's XP feature called "Fast User Switching". Note that as far as I know, Fast User Switching is not available on computers who are part of a network domain, so if you're playing D2 at work or something, then you won't be able to do this (besides, you should be working anyway ).
We'll get into Fast User Switching soon, but first I'd also like to mention that it's important you have two sets of valid CD-Keys if you wish to do this. When you log onto battle.net, it'll authenticate both the D2 Classic CD-Key and D2 Expansion CD-Key, even if you're playing Diablo II: Lords of Destruction*. The only way to have two copies of Diablo 2 logged onto the same battle.net realm at the same time is if both copies have a unique D2 Classic CD-Key and D2 Expansion CD-Key (totaling 4 CD-Keys).
- If you do not have the Diablo 2 expansion, then battle.net will only authenticate your Diablo 2 Classic CD-Key, of course.
 Fast User Switching
First, verify that you have Fast User Switching enabled on your Windows XP machine. You will need to have access to an administrators account in order to do this:
- Click Start --> Settings --> Control Panel
- Open "User Accounts"
- Select "Change the way users log on or off"
- Make sure the option "Use Fast User Switching" is ticked.
While you're there, make up a second user that will be used to run your second copy of Diablo 2.
Once this is done, you can use the Fast User Switching feature by either
- Click on "Start" --> "Log Off", and then select "Switch Users"
- Press the Windows Key + L
More information on the Fast User Switching feature of WinXP can be found on Microsoft's site.
I'm going to assume that no installation of Diablo 2 already exists. My reasoning behind this is that alot of people might not know which CD-Keys they used in their first D2 installation, and therefore might uninstall and re-install it to ensure both have seperate CD-Keys. If you already have one copy of D2 installed and you know which CD-Keys you used, then you just need to start from step 2.
1. Install Diablo 2 Classic and Expansion using one set of CD-Keys to a folder (eg: cgames\Diablo II). Make sure to patch the game up to the latest version (at the time of writing this, patch 1.11b) 2. Rename the Diablo 2 installation directory to a different name (eg: cgames\Diablo 2).
3. Uninstall Diablo 2 using the Add/Remove programs utility in Control Panel. It's been mentioned that you do not need to uninstall the game in order to install the second copy, but as of the time of writing this I have yet to see it confirmed.
4. Install your second copy of Diablo 2 Classic and Expansion (eg: cgames\Diablo II), making sure to use different CD-Keys than the ones using in the first installation. Patch it up to the latest patch.
That's pretty much it. To run both copies, start the game on one computer and then switch to your second user to start the second copy of the game there. Make sure each user profile is using a different D2 installation folder.
It's important to note that because both accounts will have the same IP Address, you will not be able to sit in the battle.net channels with both games at the same time. If you plan on having them both logged into battle.net at the same time, try to make sure that one copy of D2 is always in a game at any given time.
Also, it is possible for you to be on the same battle.net account on both D2 copies, but not on the same character. Once a character has logged into a game, battle.net will not let that same character log into another game.