How do I correct or adjust the font color?

I'm trying to send an E-mail through a personals/dating website. In order to send the E-mail, I am required to type some letters that I see in a box. I'm uming this is a security feature. I've used this type of feature on Craigslist website with no problem; however, this dating website ("plentyoffish") is a little different: while looking at a box which has both black and blue letters, I am asked to type ONLY THE BLUE LETTERS in the box. My problem is that ALL the letters in the box appear black! I contacted the dating website and they told me to adjust the color settings on my computer. I'm not super techy, but I tried a few different things, and nothing has helped. I don't know why this is happening because I can see colors on my monitor just fine. I suppose I just need enough of an adjustment to be able to differentiate between black and blue. Any help will be appreciated! :-) I'm using a hand-me-down computer and monitor: both are Dell, using Windows XP. Thank you, thank you, thank you!