MP4 Video screencaps

[anaxcrosswords]

To take a screencap of an MP4 video I pause it, use PrintScr and paste into a new PhotoShop document. But even if I flatten the image, crop it etc etc it never becomes a fixed image. I can move the entire image frame around and it behaves like a mobile window - the full video still is in the background and moving the frame just shows a different part of the still.
Does anyone know a way around this?

[Mosaic]

Possibly easier to control if you paste it into a simpler program - even paint - then crop and save as jpg.

[ChuckFickens]

Or if you have windows7 or vista (not Home Basic) use the snipping tool instead of print screen and just grab the area you want to start with.