If you use any ext. cabling, remove them and have a direct connection. Understand also, while the LCD default resolution is XYZ, your std. output from the video port/card is is usually another XYZ too, they must match or get the best possible viewing, play with it. Also, if you're in an office with bright lights, etc. and you adjust brightness/constrast to extremes viewing will diminish overall. The bigger the screen the larger some displays show thier weakness, especially when using older video ports. Thus, having a newer video port/card and more video ram increases enjoyment in this regard. Last, overall the quality of the LCD counts as well, but I think you need to adjust setting for the best match as Dell offers decent LCDs. If possible get a video display output pattern to adj. basic setting before going overboard on anything else. here's a link:
http://www.brouhaha.com/~eric/software/lcdtest/

or find something similar.

tada -----Willy Happy