I have Adobe Photoshop 7.0 and CS3 and the colors wont show they turn to black white or grey never a color?

Like when I was using the brush tool I wanted to paint red
but it only showed up grey or black or white depending on the lightness. How do I get my colors to work?

I am trying to fill a sun vector brush on photoshop CS2 and every time I fill no color shows just grey?

I use a apple computer. I keep having this problem with photoshop if i try and add any color the color always turns grey its getting me really aggravated! Any help will be appreciated.