Hit Start button, go to All Programs then Accessories, start Paint.
Hit edit then paste or better yet ctrl-v.
Then save as your choice, but choose jpeg format from drop down menu. (You may want to crop before saving.)
Then go to tinypic.com and upload your pic.
Use your pic with links provided.
EDIT: I meant to say.
Go to google.com and type "How do I post screen shots"
Hit enter and click first link.