Very Computer

I start up X windows and from then on, every time I move, create, or
change a window, pixels on the screen "get lost" .  every once in a
while I refresh the screen and it looks OK again.
I have a pentium 60 Mhz with a Tseng labs ET4000 video card and 2 Mb
videoram.  The monitor is SVGA.  Please respond if you have a solution.
 Thank you in advance........