Between the title of the thread, and the post itself, I'm not certain exactly what you want -- to get rid of the error (solve the error) or simply delete the logfile?
You can delete the log file any time after it's been created, by using the `rm` command as root:
shell# rm -f /var/log/Xorg.0.log
But it's going to come back next time you start X anyhow..
As for solving the (EE) error (if that's what you want to do), you'd need to tell us more stuff: Show us the exact copy+paste of the output in the console after trying to start X, or post for us the relevant contents of the log file. And, tell us what happens - does X start, or not? Also, please tell us what is the video card model?