Support by the community means different things to different people. For me, it
means searching with search engines, using the wikis and documentation, using
man pages, frequenting boards like this one and help forums for the distribution
that I am using or a general one like LinuxQuestions.org. The more obscure your
problem the less likely that anyone else has encountered it and the deeper you
need to dig. There is no such thing as one stop support when the community is so
broad and diverse.

I have not had streaks on my display using this computer or another one so I
have never had the troubleshoot it. I have not tried to help before because it
is best handled by someone with direct experience. Questions that I would ask
are: how much video RAM do you have, does it happen on every OS, does it happen
only sometimes or always, what happens if you use the Live CD, does it happen
with Live CDs for more than one distro, have you tried using boot parameters
from the grub menu of the Live CD, what happens if you change display managers
from gdm to kdm by installing KDE/Kubuntu, what are your monitor settings under
Settings| Preferences| Screen Resolution, is your monitor and video card
properly detected, what happens if you change the monitor type, what happens if
you change the refresh rate, have you another monitor to try and are you using
desktop effects or Compiz Fusion?

You may have answered some of these questions and I have not paid attention
because I felt someone else with more expertise would help. I am sorry if this
is the case as I see that you are frustrated.

Something you could try from a terminal is kill X with: sudo /etc/init.d/gdm
stop
Then try to reconfigure X with: sudo dpkg-reconfigure xserver-xorg
Change the settings here to something more suitable.
Followed by: sudo /etc/init.d/gdm restart

This is an old cure-all for X problems that sometimes works.