I can't play Microsoft Ants on voobly, I can launch the game offline through program files and play single player but if i join a lobby and try to launch, it goes black briefly and goes back to the lobby. Like it tries to launch but won't.

Hi reinstall ur game and delete old folder
Next do this http://support.voobly.com/plugins/servlet/mobile?contentId=360476#content/view/360476
Next do game diagnostics and follow the steps and try if works.

I've done that. And game diagnostics is unavailable for Microsoft Ants.

The weird thing is, it works offline when opening with c:/program files(x86)/voobly/gamedata/ants/ants.exe

U do voobly clean instalación?

Yes sir, Clean install of voobly and ants. still no luck. i also did tried compatability mode for windows 95 640x480 res and 256 colors with no luck.