no. theres that key on your keyboard called 'screensht' or something like that near the 'inser' and 'home' and 'scroll lock' keys. just press it, then launch photoshop or paint, create a new file, then just paste and there you go.
nohow. you gotta save the screenshot to disk (maybe with the paint programme which comes with windows: open paint, press control+V, save image) and upload the saved file somewhere on the net, then use the ['img'] tags to insert in your post