Gnomie Artim Zendeli writes:

1. Make your desktop background black — this way you can see the dead pixel.
2. Get a Sharpie marker, but keep the cap ON (you don’t want marker on your screen). If you notice, a Sharpie cap is rounded and smooth. That’s what you want to use (NOT a sharp tool or pen).
3. Gently bang on the pixel directly with the cap from the Sharpie; this will cause the dead pixel to flood with color and bring it back to life. You don’t want to smash the screen with the pen but give it a good couple bangs.

(Note: Not all dead pixels can be fixed.)

Thats it, I THINK this fix only works on LCD screens..

My friend had this dead pixel on his 17″ LCD and I came across a blog explaining how to fix a dead pixel. I sent him the email with the fix, not expecting it to work at all. The next day I got an email stating that his dead pixel has OFFICIALLY been brought back to life.

Hope this helps!