My laptop has Ati Radeon 7500 Mobile graphic adapter.
I can not set the screen resolution to above 800x600.
If I set the screen resolution to 1024*768, it is out of order.
I have downloaded and setup ATI's latest driver but everyting is same. Tell me please, how to do that.
Thanks.

As root booted into runlevel three fix it...........

When the grub splash screen is displayed press any key
Highlight the Linux boot choice and press the 'e' key
Hightlight the line that starts with 'kernel" and press the 'e' key
At the end of the line add a space followed by the number three (3)
When done press the 'Enter' key followed by the 'b' key

Log on as root when prompted.

Or exit out of the GUI session, press the three key combo of Ctrl+Alt+F1 and log on as root then type 'init 3' watch the screen and wait a few seconds after the messages stop then press the 'Enter' key.

Now type something like;

system-config-display --reconfigure --set resolution 1024x768 --set depth 24

When done test by typing; startx


Additional switches and options are available for help type;

system-config-display --help

Hint: you may want to add the --set driver option and use the driver as suggested by ATI's instructions.

Thank you Lenard. I did solve the problem. I just edit the X11/xconf file's SECTION "SCREEN" part.
I added the "1024x768" and Depth 24 (as you said). Everything is OK now.
Thank you.