If you just updated to 10.04 and you might be experiencing issues with your function keys supposed to control screen brightness on my Asus UL30a It worked fine in 9.10.
Open up Terminal and enter the following
gksudo gedit /etc/default/grub
Look for the line that says GRUB_CMDLINE_LINUX and add this
Save it and then update Grub
Reboot your system.