I am new to this forum so please pardon my ignorance on some basic issues.  We are running Dell T3500, Windows7 (64 bit), W/6GB ram, NVidia FX-580, and SW2007 (soon to upgrade to 2009).  What are the best video card settings for this combo?  I am currently getting the ocasional "black" backround/boxes.  Also, when I go from one SW file to the next it is as if the video card is not "refreshing" the screen because some parts of the screen have black backrounds.  Thank you for the help in advance.

-Paul