Easy step by step guide of how to post screen shots in forums etc.
Fistly make sure what you want to screen shot is "live" by left clicking your mouse on it.
Then press the Alt button and the Print Screen button.
Nothing will appear to have happened bit don't worry.
Open your photo editing software ( I swear by Paint.net) ordinary paint that comes on your pc is also fine.
Click on the edit option in paint and press the "paste" option, your picture will appear.
Edit out the bits you don't want or save it as it is, click "save as" and give it a name.
Then open an account at paint bucket or some other picture storing site and upload your picture to it. There are many free sites to do this with.
In the topic where you want to post look for the picture/insert image option. Usually a small image that looks like a picture

click on and save the direct link option on your photo in photobucket and copy the link.
Paste the link in the insert image option on the forum
Depending on which forum you might have other options like this

just paste your code and align as shown.
press save/post and hey presto your picture will be there.