Ubuntu graphical errors while installing

As a rule always install ubuntu distro with alternate install C.D , as it will ensure smooth installation 9 out of 10 times

if there is any graphical problem then try this

install from the boot prompt try this

boot: install acpi=off vga=771 noapic nolapic hw-detect / start_pcmcia = false

for more info when u boot from ubuntu cd
menu will be shown with, at the bottom it is written F1 help F2 language ......

try pressing F6 and read all possible error conditions and their solutions

then i think it is the esc key to get the boot: prompt
then install from there