1)   JScreenFix 1
JScreenFix is a Java applet and Java webstart application that helps re-energise stuck pixels and remove burn-in on LCD and plasma screens by randomly switching on and off red, green and blue colour cells very rapidly.

 2)   Freedapps Desktop Drape 2.0
Freedapps Desktop Drape instantly blanks your computer screen, except an area of the screen you want to focus on (such as a YouTube video, a photo or a text editor). Use it to focus on your current task and make all other windows (or ads) disappear.