video card issues

I am running a Asus 9200SE ATI Chipset 128mb AGP 8X, it is developing a white blur in the upper left hand corner of the screen, So I purchased a ATI 256 9550 8X Agp, the problem is, that it pixilates in prohicies on boss's and close up objects and the stairs in nightfall pixilate ( look like squares and blocks ) other people I have heard run this card with no problem, So I am trying to figure out what my issue could be.

Thanks