After routine updated my Ubuntu 8.10beta yesterday,I found mouse,keyboard &touchpad all of them had no response,well beta is beta :), I solved this issue by adding below lines to /etc/X11/xorg.conf. If you are not familiar with terminal mode,you can just use your live cd into the Ubuntu, and then go to Places->the Partition in which your Ubuntu 8.10 beta installed,open the terminal and run:sudo nautilus ,and then just open the /etc/X11/xorg.conf with gedit and add below lines,save and restart the computer.

Section “InputDevice”
Identifier    “Generic Keyboard”
Driver        “kbd”
Option        “XkbRules”    “xorg”
Option        “XkbModel”    “pc105″
Option        “XkbLayout”    “us”
EndSection

Section “InputDevice”
Identifier    “Configured Mouse”
Driver        “mouse”
Option        “CorePointer”
EndSection

Section “InputDevice”
Identifier    “Synaptics Touchpad”
Driver        “synaptics”
Option        “SendCoreEvents”    “True”
Option        “Device”    “/dev/psaux”
Option        “Protocol”    “auto-dev”
Option        “HorizTwoFigerScroll”    “True”
Option        “VertTwoFingerScroll” “True”
EndSection

Section “ServerLayout”
Identifier    “Default Layout”
screen “Default Screen”
Inputdevice    “Generic Keyboard”
Inputdevice    “Configured Mouse”
Inputdevice    “Synaptics Touchpad”
EndSection