Troubleshooting X server resolution problem in Linux

X was in a very bad shape after I followed the workaround for the problem in FC4. Only 600X800 resolution was available. tried many things(Xorg -configure,system-config-display..etc),upto the downloading a new X11 and not knowing what to do. Finally went to the 600x800 mode only went to display resolutions and saw that video card is incorrectly indentified. Changed it to Intel 815e and restarted X. Now its working. I was thinking of reinstall FC4 to FC3 itself for this. :(