I've installed Ubuntu 5.10 and Ubuntu Dapper Flight 5 in my PC but the sound doesn't
work at all. Aside from that, whenever I shutdown, the GNOME just disappears leaving a black screen with a blinking cursor at the upper left corner.

How do I fix this?

Is all this in breezy or dapper or both?

try: sudo dpkg-reconfigure gdm (for the display issue)

(sound)
This board uses an intel chipset right? Please post output of lspci ... (and read the stickies). We'll probably want to see lsmod too, and anything in dmesg which refers to your soundcard.

general:
http://easylinux.info/wiki/Ubuntu

this is happening both in breezy and dapper. but the shutdown issue doesn't happen in version 5.04.

i've tried reconfiguring GDM and that didn't fixed the problem. Not sure if GDM is the problem, because the shutdown process doesn't continue everytime i "halt" from another terminal. On the other hand, other functions doesn't work in gnome like log-off, restart... not only shutdown. I'm really confuse what is really the problem.

My sound also doesn't work... Tried alsamixer but speakers is not muted.

any ideas?

May be ACPI - I'd check the BIOS settings for this: it is possible that the upgraded versions are seeing something in your BIOS that got ignored in hoary. (And sometimes it is set so the system reboots on powerdown in some way.)

Also check that acpi is enabled with: ps aux | grep acpi (show me the output).

You could try altering the kernel line in /boot/grub/menue.lst to add "noapic nolapic" ... this sometimes solves reboot/shutdown issues.

this is the output of ps aux | grep acpi:

root 11 0.0 0.0 0 0 ? S< 19:19 0:00 [kacpid]
root 3616 0.0 0.2 7600 1436 ? Ss 19:20 0:00 /usr/sbin/acpid -c /etc/acpi/events -s /var/run/acpid.socket
hal 4212 0.0 0.1 9264 832 ? S 19:20 0:00 /usr/lib/hal/hald-addon-acpi
void 4852 0.0 0.1 3944 900 pts/0 R+ 19:22 0:00 grep acpi


btw i added noapic nolapic in /boot/grub/menu.lst like so...

title Ubuntu, kernel 2.6.15-18-amd64-generic
root (hd0,6)
kernel /boot/vmlinuz-2.6.15-18-amd64-generic root=/dev/sda7 ro quiet splash noapic nolapic
initrd /boot/initrd.img-2.6.15-18-amd64-generic
savedefault
boot

but still, it didn't fixed the problem. any ideas?

hmmm - that's [ps aux | grep acpi output] the same as me.
Just to check, I did "sudo shutdown -h now, and it shutdown cleanly.

Lets eliminate acpi from the equation: add "noacpi" to the kernel line and reboot.

You should also check the bios for any hint of a setting for how it reacts to being shutdown.