x-window problem

["naveen dhankhar" <naveen_indian@xxxxxxxxxxxxxx>]

Hi,
	from last some days I was not able to run x-window form any normal user account.I can run it only by root.what may be the problem?
when I type startx it gives the following error:

Authentation failed -can not start X server
Perhaps you do not have console ownership?
I am using RedHat 7.0