First, check on your keyboard the key "printscreen" (or similary in your native language...) Press "printscreen" on the screen you wanna post. This makes a COPY of your screen. Then (on a PC) open "paint" or whatever drawing stuff, we don't care... Create a new document, and simply PASTE, and that's all !
Thanks for the suggestions but the question is NOT how to take a screen shot BUT how to post it on THIS forum. I have a screen shot of VRTool running on Win 8 and wanted to include it my reply to the post.