I guesse if you installed the new drivers without any errors and you have uninstalled the dummy drivers there has to be something with Frequencies settings? maybe the setting you have on X gives your monitor an error?
"Wrong sync ranges may damage your monitor. Consult the monitor manual for the following settings."
But please give us some more information about what drivers you have installed,what configuration you have in XF86Config, and if you are using Source.RPMS? Tar? or RPM.?