I cant take a screenshot anymore! Can anyone help??

[Fareed]

Hello I used to be able to take a screen shot using command, shift, 4/3 yet now nothing happens! Any ideas or help please?

 

[Cory Cooper]

Hello and welcome.

-Which model Mac?
-Which version of OS X?
-Have you tried using the Command and/or Shift keys on the other side of the spacebar?

C