Flatscreen refresh rate trouble

Hi,

My CRT monitor broke recently, so i connected up my brothers flat screen, but just before windows starts, i get the msg 'mode not supported', i managed to load in safe mode, but that wont let me change the refresh rate, as it only shows up as 'default monitor'

earlier on it managed to load in VGA mode, and i changed the refresh i that to 60hz, but i still got the same msg, more annoyingly, when i went to run it again in VGA mode i started getting the same message!

now how would i go about fixing this problem? prefrably without having to get into VGA mode, although advice how to do it in VGA mode would also be useful

i suppose getting a CRT monitor would work wouldnt it? unless this problem is coming from somewhere else..

thanks!