I just wanna report a solution I found to play MTA correctly...
on the release day I tryed all the solution I found on this board and noone fixed the freezing problem.
Today I wanted to try again with an other procedure and the game started successfully.
-Right Click on Multi Theft Auto.exe, compatibility, Win 95 (that's right), apply.
-Right Click on GTA_SA.exe, compatibility, Win XP SP2, apply.
-Run MTA, as an Administrator, now you should not freeze.
-Settings -> video -> unflag all.
-Reboot MTA and join a server.
If u don't do the fourth step you may crash on joining