Hello to everyone !!!
i am new to linux and have just installed Red Hat 9.0 along with Win98 and WinXP. While installing linux it said "unprobed monitor". I have 'LG Studioworks 440Si' monitor. From the list shown, while installing linux, I chose LG Studioworks 44i. I have completed the installation successfully.

The problem is that X window is coming in only 800x600 mode and all the icon and text are appearing very large and the desktop is not looking pleasant. I tried to change the resolution to 1024x768 but it is not accepting it. I am using 1024x768 resolution in my WinXP and Win98 and it is working fine there. Also during the installation of linux, it has correctly chosen the video card as Intel 845. I have Intel 845 chipset.

Please help me out to change the resolution to 1024x768.

What do you mean by that? Are you getting error messages? How did you try to change the resolution?

Its not throwing error but detects monitor by itself to unknown type. And when I change the resolution to 1024x768 and log in again it automatically sets the resolution to 800x600. But it takes the resolution 1024x768 with 256 colors and not with thousands and million of colors.

Try this:
1) exit X
2) log in as root
3) type "cp /etc/X11/XF86Config /etc/X11/XF86Config.old"
4) open /etc/X11/XF86Config in a text editor
5) find the "Screen" section
6) change the DefaultDepth to 24
7) in the "Display" subsection with Depth 24, change the "Modes" line to say:
Modes "1024x768" "800x600" "640x480"
8) switch to virtual console 2 (by pressing Alt+F2)
9) log in as a non-root user
10) type "startx >xfree.log 2>&1"

if anything goes wrong, restore the old configuration file with "cp /etc/X11/XF86Config.old /etc/X11/XF86Config" and post the contents of xfree.log on this forum

type
XFree86 -configure

and follow the path

what you could need :
man vim
vimtutor
man nano
man XF86Config-4
man XFree86