some questions about fedora core 3 in my own pc
 

my pc is celeron2.4 ;256 ddr;80g; and fx5200
now i install the fc3 in my pc,and i also installed the nvidia drivers for linux
but i do not know how to change my monitor's refresh rate
i feel my eye not comfortablely and now my refresh rate is about 65HZ
how can i change it . i am a newer in this forum and my english is poor
and i also have another question that use "yum update" to update my os
but now the space in my disk is not enough i want to cancel update and remove the files which it has just update in my disk so that i can have more disk space .but i do not know where the files store in
thanks a lot for anyone who want to answer my questions

Open your /etc/X11/xorg.conf (or XFree86 for older versions) in a text editor. Then scroll down to the ' Section "Monitor" ' section, and change the refresh rates from there.

Fedora may also have some GUI tools that can do the same, look around in your "settings" and all