Acer TravelMate 4500 & Ubuntu 8.04

Hello! I have an ACER Travel Mate 4500 laptop with ATI graphics (9600, I believe), working fine (WIFI included) under Ubuntu from 6.04 to 7.10. When I try to do a clean install of 8.04 version the problems start. I even tried to install Xubuntu 8.10 with the same results: the grub and splash screens are not visible, and the system freezes after a while, some times boot start ok and I can see the desktop, then suddenly after max. a minute, the screen goes black and the computer stops working.A funny thing: I attempt an install when I had a second screen attached to the docking station and all went fine, perfect booting, every thing in order! but only using the system like that, If I tried to use only the laptop , the same old story happens :-(I belive the problem has something to do with some incompatibility of ACPI, but I don't have the skills to find out by myself. Is there somebody out there who knows a solution to this?

Same here!

I have the same problem on my 4500 too.  I'm running Kubuntu 8.10 with same symptoms.  The screen goes black after a few seconds, non responsive. Seems OK in recovery/command mode.  The system has been running XP for the last few years with no problems, so I'm 100% sure this is down to Ubuntu (especially now I've found someone with the same fault).Did you ever get a fix?  Or is a rollback to the old version the only way forward?Cheers