So, I have contacted the support, and had these answers :
--> Completely uninstall the game
--> Remove the 3dxchat game folder
--> Clear your registry
--> Add the game and patcher to the exception list of your firewall and antivirus
--> Download the installer of the latest game version
--> Discord in settings turn off "Share your detected activities with others"
--> Discord delete 3dxchat from the registered games
--> Disable programs (FPS monitor, reshade)
--> Disable background applications one at a time and attempt to launch the game
I have tried all of them, and none work, 3dxchat still refuses to launch. I will switch from Windows 7 to WIndows 10 next week, and try again. But if it doesn't work, I will ask a refund at the support.