Create new xorg.conf file :
Code:
su -
nano /etc/X11/xorg.conf
Add this :
Code:
Section "Device"
	Identifier	"Configured Video Device"
	Driver		"vesa"
EndSection

Section "Monitor"
	Identifier	"Generic Monitor"
	Option		"DPMS"
	HorizSync	30-71
	VertRefresh	50-160
EndSection

Section "Screen"
	Identifier	"Default Screen"
	Device		"Vesa"
	Monitor		"Generic Monitor"
	DefaultDepth	24
	SubSection "Display"
		Depth		24
		Modes		"1024x768" 
	EndSubSection
EndSection

Section "ServerLayout"
	Identifier	"Default Layout"
	Screen		"Default Screen"
	InputDevice	"Generic Keyboard"
	InputDevice	"Configured Mouse"
EndSection
Press Ctrl+X, Y and hit Enter key to save file. Reboot machine.