All you need to do is do a search to find the V&H refreshrate for your monitor, and edit /etc/X11/xorg.conf or I think RedHat uses /etc/X11/XF86config
Also if you want a free Ubuntu disk take a look at this
page. I think all you need is a valid email address and they will ship it free of charge. Note: it takes awhile to get over here to the states but it may not take long at all as I think they are located in Africa.