Here's an extensive step-by-step tutorial on how to run multiple Diablo II windows using multiple CD-Key's. Remember that is tutorial is offered as-is, and no guarantees are made that this will in fact work for you.

The only pre-requisite is that you have D2Loader (downloaded from here) installed and properly set up. For this tutorial we will be using Onlyer's CD-Key Refiller, which you may download by clicking on the link in the left panel of the site.

Step 1 - Setting up Onlyer's

Ok, now that you've downloaded Onlyer's CD-Key refiller, the first thing you need to do is unpack it. Preferably right into your Diablo II folder (usually located in C:\Program Files\Diablo II), as that's where some of the files need to be anyway and it's the location where we will be working in.

Extraxt all files in d2-cdkey.zip to your Diablo II-folder.

Step 2 - Filling in CD-Key information

Next, you will need to fill in the information about your secondary CD-Key into the auto-cdkey.reg file. Right click the file and choose Edit to open it, then fill in your CD-Key information in the specified locaiton.

Right-click and choose Edit.

Fill in your CD-Key information.

Step 3 - Creating the .MPQ file

Now you will want to create the .mpq file, which is what Diablo II uses, containing the CD-Key information. For this, we will use Onlyer's CD-Key Refiller, which we downloaded earlier. Run the file d2-cdkey.exe and click on "REFILL BOTH CDKEYS".

Click on this option in the window that opens.

Note: If the file cdkey.mpq (or the file you specified in auto-cdkey.reg)already exists, nothing will appear to happen when you click the option above. Perhaps you'll see a window just pop-up and disappear again. This is normal and is just what's supposed to happen.

Alternative, adding third cd-key: Should the file not exist (i.e. if you decide to add a third CD-Key and name the file cdkey2.mpq in the auto-cdkey.reg file), then a Choose Folder-dialog will pop-up asking you where you want to install Diablo II. You should choose your Diablo II folder (usually C:\Program Files\Diablo II) and click Ok. The program will say this folde ralready contains an installation, dont mind it and choose "Install Anyway". It will then created the file cdkey2.mpq (or any file you specified in auto-cdkey.reg) in the Diablo II folder.

Step 4 - Creating the shortcut

Now that you've got all you need to run the secondary CD-Key, you only need a shortcut to make it run. If you already have a shortcut to D2Loader, you should preferably use that one to copy anc create a new one. Otherwise we will make a new shortcut.

Right-click d2loader.exe and choose Copy. Next, right-click your Desktop (or whereever you want to put the shortcut and select Paste Shortcut.

You should now have a shortcut to D2Loader on your desktop. Right-click it, and choose Properties (the bottom option).

Select properties from the menu.

While in the Properties dialog, you will want to add a command line argument to the "Target" field. You should add "-mpq cdkey.mpq" at the end of the Target string. This tells D2Loader to use that file and the information contained within (in our case, the new CD-Key) instead of original game information. Another helpful argument I recommend is -w (window mode).

This is probably how the Properties dialog will look like.

Add the specified arguments as described above.

Step 5 - Done!

Now you're done and all you need to do is run the new shortcut to start playing using your new CD-Key. Should you want to add even more CD-Keys, just repeat Step's 2 to 5, using a different filename instead of cdkey.mpq.

Good Luck!
/Rodik