World of Warcraft Classic 1.12.1
Save the file and start the game with Wow.exe.
Remember that you cannot run WoW from inside an archive — you must extract it properly first.
If WoW refuses to start, try running Wow.exe as Administrator (right-click → Properties → Compatibility → Run as administrator).
If you get a black screen but can hear music, install DirectX 9.0c (available from Microsoft).
If you cannot save realmlist.wtf, move the WoW folder outside of Program Files and try again. Also make sure the file is not set to "Read Only".