I recently installed Redhat 9 onto a Sony Vaio PCG-C1VPK ("Picturebook" I believe..the tiny one).
The system seems to boot fine, but when it reaches the GUI login and I enter a username and password, it immediately reverts back to the text login. In between, there's a brief error message that flashes, but it happens too quickly for me to read what it says. After several seconds at the text login screen, it goes back into the GUI login as if nothing happened. Several iterations cause the thing to give up starting X, at which point it goes back to the text login screen for good. There, repeated attempts to login both as my normal user and as root simply return back to the same text login screen.
It does recognize bad passwords as bad, but good passwords just cycle the login screen.

I edited the grub "kernel" line and added "single" to the end of it, such that when I boot up from this, I get a text-only prompt as root. I changed the root and user passwords here thinking that this might change something, but it did not. I can execute some commands at this root prompt, but this is hardly what I would consider an acceptable solution.

Any thoughts?

This looks like something that is called after login isn't there.
Do you have a window manager installed?

What happens if you login on the console and do "startx"?

when I got the root prompt from editing the kernel line in grub to include the "single" designation, running startx gives an error to the effect that it can't open display 0 or the like.
I figured there may not be an appropriate display defined (since during installation it could not find a monitor type), but I didn't think that this would effect a login in text mode after it gave up trying to login in X.

I reinstalled and had it boot into text mode by default. It now does the login fine and startx puts me into Gnome. Perhaps something went wrong during the first installation.

anyway thanks.

I would like to put rehat 9 on my pcg-c1vpk. does it install all drivers by it self? Could you send me a link to download the os? maybe the drivers if needed. I will be new to linux so bare with me, please. thanks for your time. maybe I can return this favor.