i think i resolve the issue but make changes in Xorg.conf file however i do not know what i write in the conf file i just copy and paste below data to /etc/X11/xorg.conf
root@homelab:~# cat /etc/X11/xorg.conf # nvidia-settings: X configuration file generated by nvidia-settings # nvidia-settings: version 1.0 (pbuilder@c203) Tue May 18 07:56:38 UTC 2010 Section "ServerLayout" Identifier "Layout0" Screen 0 "Screen0" 0 0 InputDevice "Keyboard0" "CoreKeyboard" InputDevice "Mouse0" "CorePointer" Option "Xinerama" "0" EndSection Section "Files" EndSection Section "InputDevice" # generated from default Identifier "Mouse0" Driver "mouse" Option "Protocol" "auto" Option "Device" "/dev/psaux" Option "Emulate3Buttons" "no" Option "ZAxisMapping" "4 5" EndSection Section "InputDevice" # generated from default Identifier "Keyboard0" Driver "kbd" EndSection Section "Monitor" # HorizSync source: edid, VertRefresh source: edid Identifier "Monitor0" VendorName "Unknown" ModelName "Acer AL1914" HorizSync 30.0 - 80.0 VertRefresh 60.0 - 75.0 Option "DPMS" EndSection Section "Device" Identifier "Device0" Driver "nvidia" VendorName "NVIDIA Corporation" BoardName "GeForce GT 240" EndSection Section "Screen" Identifier "Screen0" Device "Device0" Monitor "Monitor0" DefaultDepth 24 Option "TwinView" "0" Option "TwinViewXineramaInfoOrder" "CRT-0" Option "metamodes" "1280x1024 +0+0" SubSection "Display" Depth 24 EndSubSection EndSection root@homelab:~# can anyone tell me why it worked. it took my whole day. why it is so hard for a user to use GUI in linux. i love debian linux but in GUI it is really pain (finding the right driver, patching kernal ETC) if things are that much easy as in Microsoft i think linux can rule the Desktop world as it is the best choice of server side. but please do explain me , anyone , why above configuration work for me, even my card model is deifferent still my moniter is unknown. my hardware model is "Dell 460 workstation with nvidia fx3500" Thanks