for installing fc4 , or even ubuntu , i got this problem
after booting from vmlinuz and initrd (from both cd and ftp) display i got was very scattered.
I was not able to make out from that display. ( it was a default display of blue window and black background).
I have debian already installed on the laptop.(its in working condition)
so what should i do? 
Ctrl+Alt+F1 and setup your X 
How to setup x .
Your post isn't much more helpful than 'help my windows is broken how I fix it." Check out the manpages of the programs in question, and google "x11 <my videocard>", XF86config, etc. We can't help you without knowing anything about your system.
but to setup x os should be installed. and I dont have any os on the laptop. I am talking about the screen that appears after booting from the cd to install the os(fc 1, 2,3,4 .., ubuntu). and i am not talking about the graphical interface but Text based installation.
so please help me.
Good to know.
Debian's rather barebones as I recall, so I doubt it's trying to switch to some fancy video mode to just use text. Other distros often do, to make a fancy looking console, or make the console wider, etc; that may be why debian works and these don't. Video compliance on laptops is bad. If there's some sort of 'no framebuffer' boot mode or kernel selection, use it.
Beyond that, it would be really, really nice to know what your system actually is.
during the bootup option by setting the mode option one can set his/her display.
so in my case vga=771 worked.
thanks to vipul.