I am using fedora
it was loading before now it is not
it goes throught he first load screen
then another load screen with the gui
then it gets to the third and then at smart it stops and gets an error

I cant read the error becuase i only have half a screen

screen flashesh alot at a prompt for some reaosn it says COMCAST login
but i can login as my user name
and stilll go to super user

any way to determine the error and restore the os so it loads?

Hard to say, since you don't say what VERSION of Fedora, on what hardware, with what desktop environment. You also don't say what happened, to cause the problem.

Since you can still log in, Fedora has obviously already loaded. You're having a problem with X windows. If you didn't change anything, your video card may be having a problem, your monitor cable may be loose, etc. Check those things.

You can also boot to text-only mode, runlevel 3. If you still have "half a screen", you've got hardware issues. If not, you can at least check the error message with half a screen.

the same as above ???
With out knowing What version of fedora AND your hardware ???
--- This is only a guess ----

by chance did you update the system???
if so was a new kernel in the update ?
if so Did you also update the driver for your 3d card ?