Is a blue screen the same as a black screen?

I appreciate your site, and will refer to it often. I am not real hardware literate, so hear goes what may be a silly question. I read the Q & A's related to my problem of not being able to get to desktop when re-booting. I tried the various tips, however, I still find that the machine brings up the Apple logo with the swirlly thinking symbol (takes awhile, but then will boot as far as the Apple OS-X logo and loading bar blue scan cmpletes, then, the screen goes blue, like it will begin setting up the desktop, but then it just remains blue...mouse can move, but nothing registers on the desktop. Thanks for any help you cn give! Pastor Cindy