1)weird display 2)Can't install, PC hangs everytime

1)after a few minutes of startup my display seems to shrink
from the bottom up, and my whole taskbar disappears with
it. The top part of my screen looks as per normal, i can
even click on the icons and they will run. but the bottom
part of my screen slowly shrinks then disappears totally.
Imagine holding the bottom edges of a curtain and slowly
lifting it up. So from the front, you can't see the
bottom edges no more. it's exactly what's happening to my
screen.
2) My PC hangs whenever I try to install anything. Whenever the PC hangs, there is no error msgs. Everything just
freezes. Even Ctrl+Alt+Del has no effect. And it doesn't
matter whether I'm installing over the network or from
local directories, it will still hang, sometimes in the
beginning of installation, sometimes in the middle,
sometimes almost the end. But it will definitely hang.
Please kindly help

try booting in safe mode, if it still does the same thing ,look for the mointor controls and set them back to the default setting. it sounds like the mointor is going.on part 2 it sounds like a memory promblem. take out all but 1 memory chip if you can and see what happens, if the same thing happens take that one out and insert the oter one. if that dosn't do any thing try a on line viruis detection at www.pandasoftware.com, ad see if it finds anything. let me know waht you find. hitekrednk@sbcglobal.net.