I've never done anything other than press the PrtScn key and then use Paint.
Another alternative is to use A Thousand Words.
2. Follow the wizard to capture a screenshot
3. Use the built-in editor to resize, edit, or re-capture your screen shot.
4. Your screen shot will be saved to your desktop when you finish the wizard.
You can post the screenshot in your next post as an attachment.
Just below the area where you write text in a post there is the Post button, to the right of this is More Reply Options.
When you click on More Relpy Options you will see Attach Files and Browse, click on Browse, this will open Pictures on your computer, click on the image you want to post, then click on Attach This File, then Add Reply.