when i was trying to install the elder scrolls 3 a message appeared saying that the installation can′t work because the part "Meshes\cursor.nif" and i can′t play now

somebody could help me?

That file seems to have gotten left behind during install, it happens occasionally.
Your best best bet is to completely uninstall, and then re-install the game.
Turn off your Anti-virus program when you install (and make sure all other programs are closed too, of course) because sometimes they interfere.

very tanks, but i suceed doing one thing:

i founded one folder "setup" and ran that, and now I CAN PLAY MORROWIND 3!!! VERY THANK YOU TO HELP ME I′M VERY HAPPY AND GRATEFUL =D