Windows XP and Monitor Problems

a) Computer is turned off and monitor remains on. Window
appears with three broad vertical bands one red, one
green, one blue. After a few moments the color bands
switch places in relation to each other e.g green becomes
red, red bcomes blue; blue becomes green. repeats every
frew seconds.

Is this window a screen saver for the monitor? If not is
the behavoiur normal? What is causing this activity?

b) Also, sometimes the background behind the window
described in a) shimmers. What is the cause and fix?

c)On cold startup sometimes the monitor clicks on and off
repeatedly before the windows XP login window appears.
What causes this and what is the fix?

d) Sometimes while working in excel the screen will
shimmer, shift to the left a few milimeters and after
awhile shift back to normal. What is teh cause of this
activity and the fix?

Any help would be much appreciated.
Thanks Richard Morettin