I think that the problem is that the open source driver (xserver-xorg- video-ati) doesn't work for our graphic card (My computer has also an ATI X700).
I updated from dapper to edgy via Internet and I installed the propietary driver xorg-driver-fglrx, and it works for me. I had to add these lines on my xorg.conf file: Section "DRI" Mode 0666 EndSection -- Ubuntu Edgy Knot 2 live CD doesn't work on Acer Aspire 1694WLMi https://launchpad.net/bugs/59638 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs