For some reason when I install just Morrowind, it runs fine, but when I install Oblivion too, both of them fail to launch, only running in the background and I have to stop them in task manager. Furthermore, the gog version of sw battlefront a jedi outcast do the same, just running in the background.
It started maybe a week ago. Since then I reinstalled my Windows 7 64bit Ultimate several times to make sure it is not my computer, however the problem still exists. There was no problem with them before. I don't know what happened but I really want to play them both. I've tried compatibility modes, reinstalling directx, microsoft c++, my drivers are up to date, and my rig hasn't changed either.
Do you guys have experienced such a misery and if so, have you managed to solve it?

Sounds very strange... I don't have Oblivion on GOG, but on Steam, and I've never had any problems running it alongside Morrowind or any other game. I'm not saying it can't happen, but I don't know what could be causing it.

THANK YOU!!!! This trick solved it! It is finally working, thank you so much! :)