Just click the PrtScr button.
The image goes to your Clipboard and sits there until you paste it somewhere. For the purpose of FC, you want to paste it in the PAINT (software).
To bring up the PAINT software, click on START, All Programs, Accessories and then PAINT. You may have to scroll down the list to find it.
Once you've used PAINT, it may show up in the list of recent programs you've used that show up when you click START.
When you click PAINT, the PAINT workpage will come up. Click on PASTE.
This bring up the image you just put on your clipboard (ie the screenshot)
You now can use PAINT to CROP (define the portion of the screenshot that you want to save -- clip Crop again to confirm the change.),
use the ERASURE to remove items you want to remove (ie your email address and the ID of the transaction -- and anything else you don't want the world to see.
If you make a mistake, I believe you can just click PASTE again and the original image will come up again.
When you are happy with the modified screenshot, click on File icon (upper left hand corner) and save the image using the SAVE AS link. You need to provide a Title for the image and define the extension (see drop down menu provide for the TYPE line-- I use jpeg)
When you define your Title, make it something that will be easy for you to identify. I use FCPOPmmddyyy.
Save the picture image in your shared picture library.
FYI: you can also paste the image into an email. Not that you would want to do that for your FC POP -- but if you ever wanted to send an image of something via an email, you can create the screenshot and paste it onto an email