Photoshop :: CS3 - Eyedropper Tool Uses A Color That Is Washed Out By Comparison?

I have the full CS Suite 3 and my issue is with the Photoshop aspect. It has worked for me beautifully for many years and, unfortunately, has come into a problem recently. When I select a color using the eyedropper tool (sample size 3 by 3 Average) it selects the color. Then, upon attempting to paint that color, it uses a color that is washed out by comparison. It selects the right color but the paint brush (I'm using the standard, 27 pixel soft brush, normal mode, 100% opacity, 100% flow) will not paint that color. It looks like it's adding more white to it or adding a muddled grey color. I'm not amused with this at all.
 
I'm not certain whether it is my having accidentially hit something as to make this happen or if it is the program glitching. I uninstalled and reinstalled and, unfortunately, am still finding the problem. I will try uninstalling and reinstalling again (this time deleting all the preferences) to see if that may fix it. It does this with multiple images (all .psd files, multiple layers) so I know that it's not the single file being corrupt.