What part of X causes major display problems?

["Seneca Cunningham" <seneca@slemish.com>]

I have just upgraded X from 3.3.6 to 4.1.0. After completing the upgrade, I
changed from tty1 to X's display and saw the image on the screen consisted
of vertical lines running down my display, the top of the lines were 1 pixel
in width and the bottom width was 3 pixels, with 2 wide black horizontal
lines running across it. Only the highlighted edges of the login box
appeared. No mouse cursor or text is visible on the screen. This continued
after rebooting, but the colours of the lines sometimes changes after
rebooting.

When Ctrl+Alt+Bksp is pushed, I see tty1 for a moment, the screen goes
black, then, a few seconds later, the screen goes back the way it was. It is
possible to login and out when the screen is like this, the cursor is
visible as 2 short horizontal lines with a width of 1 pixel.

How can I find out what part of X is causing this problem, all of the bug
reports of similar problems that I have seen and checked are at least half a
year old, and all say that it was fixed, and these are in older package
versions  than mine.

Thanks for any help,

Seneca
seneca@slemish.com