Blizzard stores "Diablo II" character data for realm players on the Battle.net servers, so you can pick up your adventure from any computer with the game installed. Single player and open characters, on the other hand, save to your local computer, so you need to move the save files when switching to another computer. Before copying saves, make sure both computers have the same version of the game installed, and install "Lord of Destruction" expansion pack on the new PC if you had it on your old computer.
Single Player and Open Characters
All non-realm "Diablo II" characters are stored on your hard drive in one of two places. Usually, the game keeps save files within the Save folder in the "Diablo II" installation directory -- typically C:\Program Files (x86)\Diablo II. If you don't see a Save folder, look in your user data folder: Press "Windows-R," type "%localappdata%\VirtualStore\Program Files (x86)\Diablo II" without quotes and press "Enter." Copy all files within the Save folder onto a USB drive or online storage (or both, to be safe), and from there copy them to the same location on your new PC.
As long as you always log in with the same Battle.net account, realm characters transfer between computers automatically. When you change machines or play on a friend's PC, set the gateway to the correct region before logging in. If you have the wrong region selected and connect to the wrong realm, your character list appears empty.
How to Edit Diablo 2 Characters in Battle.net
"Diablo 2," despite being released in 2000, continues to be enjoyed by millions of players worldwide, in no small part because of...