hi,excuse my poor english,but i will try to explain my problem
i 'm under ubuntu 8.10 and when want to go out suspend mode by openning my laptop i get a black screen and i must reboot evry time i do this operation.
so please if somone did get an issue for this problem i would thank him a lot.

Not much info here...

I presume you've tried moving the mouse

Perhaps X is crashing, what happens if you run CTRL+ALT+BACKSPACE when the screen is black?

I just solved a similar issue. The available documentation is pretty fragmented, but there are a few consistent points. In my case, it was fixed by passing an option to the video card.

Please post the make and model of the laptop and the video card.

Also post the relevant entry in /boot/grub/menu.lst (If you have a standard installation where the bootloader was installed by Ubuntu, it will be the first entry, and will have the general form of:
title ubuntu
root (hd0,0)
kernel /boot/vmlinuz ...........
initrd (not always used)