How can I take multiple screenshots from a PC game during playing?
The depends 100% on the game in question.
However, if your game doesn't natively support it, FRAPS is probably your best solution.
Xfire will take screen shots on almost every game it supports.
Since the other answer covers only the Windows PC operating system, here are a few more methods for other PC operating systems.
Mac OS X
Just press ⌘ Command+⇧ Shift+3 to take a full screenshot.
For an arbitrary selection press ⌘+⇧+4 and then use the mouse to select what you want to capture.
To capture a window use the same combo as before, then press ␣ Space and then click on the window you want to capture. You may also do this to capture menus as well.
You can also use
Grabto get screenshots, as well as windows, selections and timed screenshots.
⌘+⇧+3 and ⌘+⇧+4 also work in the classic Mac OS going as far back as at least System 6.
All Mac screenshot functions play a camera shutter sound to inform the user that a screenshot has been taken (at least as far back as System 7).
Grab is one way to get screenshots and window captures:
File menu in Preview also has a screenshot facility in the
This varies greatly by the flavor you install. Often there may be a utility simply called "Screenshot".
Press Print Screen will invoke the Screenshot utility and take a full screenshot.
Pressing ⎇ Alt+Print Screen will take a screenshot of the current window.