FOSS gamedev and creative worlds

I have a amazingly fast computer, and a few days ago Minetest was working fast, smoothly, but now, error messages such as : could not load mesh because could not open file character x, and failed to load OPENGL multitexture extension, proceeding without, and OPENGL only has one texture unit. Disabling multitexture. and OPENGL driver version is not 1.2 or better. are showing up, and even on single player the lag is just crazy.
PLEASE HELP!!! I LOVE THIS GAME!!!
(whats really wierd is that as i said, a few hours earlier, minetest was really fast, fps average around 80, but now...)
AND now everything is going red. It stops after turning off the SHADERS function.
I need help from a real coder who knows whats going on

Did you change any drivers?

Maybe you got another minetest version?
[spoiler=When using Windows > XP]0) close minetest
1) open minetest.conf in the minetest folder
2) change/add "video_driver = opengl" to "video_driver = direct3d9"
3) save
4) test again
5) if not working, update your video driver[/spoiler]