getting trouble after changing screen resolution
 

I am using Redhat Linux 9.0 on PIV with mercury mother board.After changing my screen resolution from 800*600 to 1024*768,system is not displaying any thing just simply displaying "Hz ?".
solution plese ...?

Do you mean you're just getting the abbreviation "Hz?" (with question mark) in a console, and the X session is unable to start?

You might try responding "60" as a good safe answer, in case some process is asking you for a refresh rate. If you monitor is an LCD one, it doesn't matter what refresh rate you put; if it's a CRT 60 is a good starting point.

If something else is happening, I think more details are needed: How you changed the resolution, if you're able to get into X Window session, etc.

boot init 3 mode
move /etc/X11/XF86Config.backup file to /etc/X11/XF86Config
after that excute
init 5 command
ok problem solved