I have just upgraded to Ubuntu 10.04LTS on a Dell Optiplex GX150, from 8.04LTS. The 8.04 has worked flawlessly on this PC, which is a secondary one. This machine is not dual boot, and the 10.04 was installed, not updated, so the HDD (300GB) was repartitioned and reformatted. 10.04 has all updates to 23Aug2010 installed.
10.04 has problems, at boot 2 msgs are displayed:
error:no suitable mode found
error:unknown command "terminal"
At end of boot, and after entry of password the main GNOME screen is presented but without the menu bar at the top and without the status bar at the bottom. Alt-F1 will give Applications/Places/System at top left but of course no status bar to retrieve minimised apps.
If restart or closedown is used a dim purple screen is presented and the caps and scroll lock keys flash and the machine freezes. The hard stop causes the "Shut Down, Restart, Suspend" etc to be presented and Shut Down will do just that.
I haven't found a satisfactory fix on the forums yet, any help will be appreciated.

sudo aptitude reinstall gnome-panel and log in again.

The shutdown thing is probably acpid related. Then again,one of my systems (clean install) would not suspend because the nvidia driver was not properly configured because the nouveau driver got in its way.

Run dmesg, there may be messages that provide more detail about the two error messages. The "mode" message may be related to your screen resolution. Do you use a vga parameter in your grub file?

Many thanks for your response, the "sudo aptitude reinstall gnome-panel" works for the first startup but not thereafter,unless the command is run again, so I guess some file is being modified.
I ran dmesg, and no I don't have a vga parameter in the grub file; here is I think the output that matters from running dmesg:

[ 20.970917] vga16fb: initializing
[ 20.970941] vga16fb: mapped to 0xc00a0000
[ 20.986523] fb0: VGA16 VGA frame buffer device
[ 21.052149] lp0: using parport0 (interrupt-driven).
[ 21.083431] agpgart-intel 0000:00:00.0: Intel i815 Chipset
[ 21.117740] dell-wmi: No known WMI GUID found
[ 21.122444] ppdev: user-space parallel port driver
[ 21.126581] pci 0000:00:02.0: detected 4MB dedicated video ram
[ 21.145332] agpgart-intel 0000:00:00.0: AGP aperture is 64M @ 0xf8000000
[ 21.151125] psmouse serio1: ID: 10 00 64
[ 21.267334] Linux video capture interface: v2.00
[ 21.356821] gspca: main v2.7.0 registered
[ 21.611969] gspca: probing 0ac8:301b
[ 21.773452] input: ImPS/2 Generic Wheel Mouse as /devices/platform/i8042/serio1/input/input4
[ 21.846999] Console: switching to colour frame buffer device 80x30

allan@allan-desktop-P3:~$ sudo xrandr -q
Screen 0: minimum 640 x 350, current 1024 x 768, maximum 1024 x 768

I'm still a neophyte at linux, have you any comments on video parameters, please?
I'm continuing to look around in the system, one only begins to learn when things go wrong!
Regards

Try removing compiz

After login press Alt+F1
longin again and run:

sudo apt-get remove compiz
sudo apt-get remove compiz-core
exit

Only way i figured not to kill gnome-panel every time i login.
I have the same system as u, still trying to figure out a way to increase performance by enabling the right driver for the i815.

Many thanks, Dark87, just tried removing compiz, it worked the first time, but thereafter I get the same problem...the error messages still pop up too...I'm starting to think about taking this machine back to 8.04LTS, there's another year of support to run; or try another dist. I feel Ubuntu haven't done themselves any favours with this release.

Hi Allan again,

Here is my final option.
Try upgrading the graphic card driver.

Url:
https://wiki.ubuntu.com/X/Bugs/Lucidi8xxFreezes

Commands that you need to run:
sudo add-apt-repository ppa:glasen/intel-driver
sudo apt-get update && sudo apt-get upgrade

by doing this i have now a very smooth system running, and no panel issues any more, suggest you to give it a try before rolling back.

Many thanks Dark87, I've tried your suggestion using sudo, but with the same result after the first reboot. I don't understand why as we are using the same systems. I've therefore gone back to 8.04LTS so I have a year before having to change...it is a secondary machine. 10.04 is running successfully on another PC of mine, an HT P4 but I do feel that ubuntu have tarnished their halo!!
Regards Allan