Yes the ATI drivers are tricky I used to always have problems but usually fix it in the xorg.conf
my older xorg.conf looked like this mind you this was back in 2008 and there was allot in here that I didn't need also it was for my 3870 the bolded line is usually what helped me out after I tried to install the driver
. I would have to access the xorg.config using vim I believe because my desktop wouldn't load and of course your xorg.conf would be allot different then mine but this kind of gives you an idea of what you mostlikely need to change, just make sure that you back up your original xorgconf .
but I suggest going to linuxquestions.org they always answered all of my questions I usually would get reply's within minutes
Code:
/.../
#
Section "ServerLayout"
Identifier "Layout[all]"
Screen "Screen[0]" 0 0
InputDevice "Keyboard[0]" "CoreKeyboard"
InputDevice "Mouse[1]" "CorePointer"
Option "Clone" "off"
Option "Xinerama" "off"
EndSection
Section "Files"
InputDevices "/dev/gpmdata"
InputDevices "/dev/input/mice"
FontPath "/usr/share/fonts/misc:unscaled"
FontPath "/usr/share/fonts/local"
FontPath "/usr/share/fonts/75dpi:unscaled"
FontPath "/usr/share/fonts/100dpi:unscaled"
FontPath "/usr/share/fonts/Type1"
FontPath "/usr/share/fonts/URW"
FontPath "/usr/share/fonts/Speedo"
FontPath "/usr/share/fonts/PEX"
FontPath "/usr/share/fonts/cyrillic"
FontPath "/usr/share/fonts/latin2/misc:unscaled"
FontPath "/usr/share/fonts/latin2/75dpi:unscaled"
FontPath "/usr/share/fonts/latin2/100dpi:unscaled"
FontPath "/usr/share/fonts/latin2/Type1"
FontPath "/usr/share/fonts/latin7/75dpi:unscaled"
FontPath "/usr/share/fonts/baekmuk:unscaled"
FontPath "/usr/share/fonts/japanese:unscaled"
FontPath "/usr/share/fonts/kwintv"
FontPath "/usr/share/fonts/truetype"
FontPath "/usr/share/fonts/uni:unscaled"
FontPath "/usr/share/fonts/CID"
FontPath "/usr/share/fonts/ucs/misc:unscaled"
FontPath "/usr/share/fonts/ucs/75dpi:unscaled"
FontPath "/usr/share/fonts/ucs/100dpi:unscaled"
FontPath "/usr/share/fonts/hellas/misc:unscaled"
FontPath "/usr/share/fonts/hellas/75dpi:unscaled"
FontPath "/usr/share/fonts/hellas/100dpi:unscaled"
FontPath "/usr/share/fonts/hellas/Type1"
FontPath "/usr/share/fonts/misc/sgi:unscaled"
FontPath "/usr/share/fonts/xtest"
FontPath "/opt/kde3/share/fonts"
EndSection
Section "Module"
Load "dbe"
Load "type1"
Load "freetype"
Load "extmod"
Load "glx"
EndSection
Section "ServerFlags"
Option "AllowMouseOpenFail" "on"
Option "ZapWarning" "on"
EndSection
Section "InputDevice"
Identifier "Keyboard[0]"
Driver "kbd"
Option "Protocol" "Standard"
Option "XkbLayout" "us"
Option "XkbModel" "microsoftpro"
Option "XkbRules" "xfree86"
EndSection
Section "InputDevice"
Identifier "Mouse[1]"
Driver "mouse"
Option "Buttons" "12"
Option "Device" "/dev/input/mice"
Option "Name" "A4 Tech PS/2+USB Mouse"
Option "Protocol" "explorerps/2"
Option "Vendor" "Sysp"
Option "ZAxisMapping" "4 5"
EndSection
Section "Modes"
Identifier "Modes[0]"
ModeLine "1680x1050" 144.6 1680 1784 1968 2256 1050 1051 1054 1086
ModeLine "1680x1050" 115.0 1680 1728 1760 1840 1050 1053 1059 1079 +hsync -vsync
ModeLine "1280x1024" 138.5 1280 1368 1504 1728 1024 1025 1028 1069
ModeLine "1280x1024" 128.9 1280 1368 1504 1728 1024 1025 1028 1066
ModeLine "1280x1024" 119.4 1280 1368 1504 1728 1024 1025 1028 1063
ModeLine "1280x1024" 113.0 1280 1328 1360 1440 1024 1027 1034 1061 +hsync -vsync
ModeLine "1280x1024" 108.9 1280 1360 1496 1712 1024 1025 1028 1060
ModeLine "1280x960" 129.9 1280 1368 1504 1728 960 961 964 1002
ModeLine "1280x960" 120.8 1280 1368 1504 1728 960 961 964 999
ModeLine "1280x960" 111.0 1280 1360 1496 1712 960 961 964 997
ModeLine "1280x960" 105.8 1280 1328 1360 1440 960 963 967 994 +hsync -vsync
ModeLine "1280x960" 102.1 1280 1360 1496 1712 960 961 964 994
ModeLine "1152x864" 105.0 1152 1224 1352 1552 864 865 868 902
ModeLine "1152x864" 96.8 1152 1224 1344 1536 864 865 868 900
ModeLine "1152x864" 89.6 1152 1224 1344 1536 864 865 868 897
ModeLine "1152x864" 86.8 1152 1200 1232 1312 864 867 871 895 +hsync -vsync
ModeLine "1152x864" 81.6 1152 1216 1336 1520 864 865 868 895
ModeLine "1024x768" 81.8 1024 1080 1192 1360 768 769 772 802
ModeLine "1024x768" 76.2 1024 1080 1192 1360 768 769 772 800
ModeLine "1024x768" 69.7 1024 1080 1184 1344 768 769 772 798
ModeLine "1024x768" 69.5 1024 1072 1104 1184 768 771 775 796 +hsync -vsync
ModeLine "1024x768" 64.1 1024 1080 1184 1344 768 769 772 795
ModeLine "800x600" 48.9 800 840 920 1040 600 601 604 627
ModeLine "800x600" 45.5 800 840 920 1040 600 601 604 625
ModeLine "800x600" 44.0 800 848 880 960 600 603 607 622 +hsync -vsync
ModeLine "800x600" 42.1 800 840 920 1040 600 601 604 623
ModeLine "800x600" 38.2 800 832 912 1024 600 601 604 622
ModeLine "1680x1050" 146.0 1680 1960 2136 2240 1050 1053 1059 1089 +hsync -vsync
EndSection
Section "Monitor"
Identifier "Monitor[0]"
VendorName "ACI"
ModelName "ASUS VW198"
UseModes "Modes[0]"
DisplaySize 450 300
HorizSync 30.0 - 85.0
VertRefresh 43.0 - 75.0
Option "DPMS"
Option "PreferredMode" "1680x1050"
EndSection
Section "Device"
#BusID "1:0:0"
Identifier "Device[0]"
Driver "fglrx"
VendorName "ATI"
BoardName "ATI Radeon HD3870"
Option "monitor-DVI-I_1/digital" "Monitor[0]"
Option "EnableMonitor" "tv,tmds1"
Option "DesktopSetup" "horizontal"
EndSection
Section "Screen"
Identifier "Screen[0]"
Device "Device[0]"
Monitor "Monitor[0]"
DefaultDepth 24
SubSection "Display"
Depth 15
Modes "1680x1050" "1280x1024" "1280x960" "1152x864" "1024x768" "800x600"
EndSubSection
SubSection "Display"
Depth 16
Modes "1680x1050" "1280x1024" "1280x960" "1152x864" "1024x768" "800x600"
EndSubSection
SubSection "Display"
Depth 24
Modes "1680x1050" "1280x1024" "1280x960" "1152x864" "1024x768" "800x600"
EndSubSection
SubSection "Display"
Depth 8
Modes "1680x1050" "1280x1024" "1280x960" "1152x864" "1024x768" "800x600"
EndSubSection
EndSection
Section "DRI"
Group "video"
Mode 0660
EndSection