What kind of computer is it? Is it an Apple display? What you're probably looking at is an issue of backlight bleed (especially if it's one corner or another). Unlike stuck pixels, backlight bleed is avoidable and can be repaired. If you put a full-screen black image on (or use a blank screen saver) and it looks blotchy or pale, you've got backlight bleed, which has nothing to do with calibration.