rifatto tutto senza errori.
'unica cosa che fa rimanere perplesso è quello del file xorg.conf

ti faccio vedere il perchè: ( ecco il file originale) ti evidenzio in rosso quello che mi fa rimanere perplesso perchè non capisco cosa devo fare( con le cose in rosso) nel mio caso seguendo la tua guida.
se vuoi guarda se trovi qualcosa di strano nel file


codice:
# xorg.conf (xorg X Window System server configuration file)
#
# This file was generated by dexconf, the Debian X Configuration tool, using
# values from the debconf database.
#
# Edit this file with caution, and see the xorg.conf manual page.
# (Type "man xorg.conf" at the shell prompt.)
#
# This file is automatically updated on xserver-xorg package upgrades *only*
# if it has not been modified since the last upgrade of the xserver-xorg
# package.
#
# If you have edited this file but would like it to be automatically updated
# again, run the following command:
#   sudo dpkg-reconfigure -phigh xserver-xorg

Section "ServerLayout"

	#	InputDevice     "stylus"	"SendCoreEvents"
	#	InputDevice     "cursor"	"SendCoreEvents"
	#	InputDevice     "eraser"	"SendCoreEvents"
	Identifier     "Default Layout"
	Screen      0  "aticonfig-Screen[0]" 0 0
	InputDevice    "Generic Keyboard"
	InputDevice    "Configured Mouse"
	Option	    "AIGLX" "true" 
	# Uncomment if you have a wacom tablet
EndSection

Section "Files"
EndSection

Section "Module"
	Load  "i2c"
	Load  "bitmap"
	Load  "ddc"
	Load  "extmod"
	Load  "freetype"
	Load  "int10"
	Load  "vbe"
	Load  "glx"
	Load  "GLcore"
	Load  "dri"
	Load  "v4l"
EndSection

Section "InputDevice"
	Identifier  "Generic Keyboard"
	Driver      "kbd"
	Option	    "CoreKeyboard"
	Option	    "XkbRules" "xorg"
	Option	    "XkbModel" "pc105"
	Option	    "XkbLayout" "it"
EndSection

Section "InputDevice"
	Identifier  "Configured Mouse"
	Driver      "mouse"
	Option	    "CorePointer"
	Option	    "Device" "/dev/input/mice"
	Option	    "Protocol" "ImPS/2"
	Option	    "ZAxisMapping" "4 5"
	Option	    "Emulate3Buttons" "true"
EndSection

Section "InputDevice"
	Identifier  "stylus"
	Driver      "wacom"
	Option	    "Device" "/dev/input/wacom"
	Option	    "Type" "stylus"
	Option	    "ForceDevice" "ISDV4"# Tablet PC ONLY
EndSection

Section "InputDevice"
	Identifier  "eraser"
	Driver      "wacom"
	Option	    "Device" "/dev/input/wacom"
	Option	    "Type" "eraser"
	Option	    "ForceDevice" "ISDV4"# Tablet PC ONLY
EndSection

Section "InputDevice"
	Identifier  "cursor"
	Driver      "wacom"
	Option	    "Device" "/dev/input/wacom"
	Option	    "Type" "cursor"
	Option	    "ForceDevice" "ISDV4"# Tablet PC ONLY
EndSection

Section "Monitor"
	Identifier   "Relisys 772"
	ModelName    "Custom 1"
	Gamma        1
	ModeLine     "640x480@60" 25.2 640 656 752 800 480 490 492 525 -hsync -vsync
	ModeLine     "640x480@72" 31.5 640 664 704 832 480 489 491 520 -hsync -vsync
	ModeLine     "640x480@75" 31.5 640 656 720 840 480 481 484 500 -hsync -vsync
	ModeLine     "640x480@85" 36.0 640 696 752 832 480 481 484 509 -hsync -vsync
	ModeLine     "800x600@56" 36.0 800 824 896 1024 600 601 603 625 +hsync +vsync
	ModeLine     "800x600@72" 50.0 800 856 976 1040 600 637 643 666 +hsync +vsync
	ModeLine     "800x600@75" 49.5 800 816 896 1056 600 601 604 625 +hsync +vsync
	ModeLine     "800x600@85" 56.3 800 832 896 1048 600 601 604 631 +hsync +vsync
	ModeLine     "800x600@60" 40.0 800 840 968 1056 600 601 605 628 +hsync +vsync
	ModeLine     "832x624@75" 57.3 832 864 928 1152 624 625 628 667 -hsync -vsync
	ModeLine     "1024x768@85" 94.5 1024 1072 1168 1376 768 769 772 808 +hsync +vsync
	ModeLine     "1024x768@75" 78.8 1024 1040 1136 1312 768 769 772 800 +hsync +vsync
	ModeLine     "1024x768@70" 75.0 1024 1048 1184 1328 768 771 777 806 -hsync -vsync
	ModeLine     "1024x768@60" 65.0 1024 1048 1184 1344 768 771 777 806 -hsync -vsync
	ModeLine     "1024x768@43" 44.9 1024 1032 1208 1264 768 768 776 817 +hsync +vsync interlace
	ModeLine     "1152x864@75" 108.0 1152 1216 1344 1600 864 865 868 900 +hsync +vsync
	ModeLine     "1280x960@60" 102.1 1280 1360 1496 1712 960 961 964 994 -hsync +vsync
	ModeLine     "1280x1024@60" 108.0 1280 1328 1440 1688 1024 1025 1028 1066 +hsync +vsync
	ModeLine     "1400x1050@60" 122.6 1400 1488 1640 1880 1050 1051 1054 1087 -hsync +vsync
EndSection

Section "Monitor"
 # 
	Identifier   "monitor1"
	Gamma        1
EndSection

Section "Monitor"
	Identifier   "aticonfig-Monitor[0]"
	Option	    "VendorName" "ATI Proprietary Driver"
	Option	    "ModelName" "Generic Autodetecting Monitor"
	Option	    "DPMS" "true"
EndSection

Section "Device"
	Identifier  "ATI Technologies Inc RV350 AS [Radeon 9550]"
	Driver      "fglrx"
	VendorName  "ATI"
	BoardName   "ATI Radeon"
	Option	    "MergedFB" "off"
	BusID       "PCI:1:0:0"
EndSection

Section "Device"
 # 
	Identifier  "device1"
	Driver      "fglrx"
	VendorName  "ATI"
	BoardName   "ATI Radeon"
	Option	    "MergedFB" "off"
	BusID       "PCI:1:0:0"
	Screen      1
EndSection

Section "Device"
	Identifier  "aticonfig-Device[0]"
	Driver      "fglrx"
EndSection

Section "Screen"
	Identifier "Default Screen"
	Device     "ATI Technologies Inc RV350 AS [Radeon 9550]"
	Monitor    "Relisys 772"
	DefaultDepth     24
	SubSection "Display"
		Virtual   1400 1050
		Depth     24
		Modes    "1024x768@85" "1024x768@75" "832x624@75" "1024x768@70" "800x600@60" "1024x768@60" "800x600@85" "1024x768@43" "800x600@75" "1152x864@75" "800x600@72" "1280x960@60" "800x600@56" "1280x1024@60" "640x480@85" "1400x1050@60" "640x480@75" "640x480@72" "640x480@60"
	EndSubSection
EndSection

Section "Screen"
 # 
	Identifier "screen1"
	Device     "device1"
	Monitor    "monitor1"
	DefaultDepth     24
EndSection

Section "Screen"
	Identifier "aticonfig-Screen[0]"
	Device     "aticonfig-Device[0]"
	Monitor    "aticonfig-Monitor[0]"
	DefaultDepth     24
	SubSection "Display"
		Viewport   0 0
		Depth     24
	EndSubSection
EndSection

#Section "Extensions"
#	Option	    "Composite" "0"
#EndSection