Printscreen not taking screencaps

I'm on XP Pro SP1, and all of a sudden the PrintScreen key has decided to stop taking screencaps.

As far as I know I have not modified anything that could have caused this, I've not done anything out of the ordinary or installed any new programs within a month or so.

When I press the key it just doesn't do anything - I have gone into photoshop but the paste option isn't there. Alt-printscrn DOES work though...

When I do alt-printscrn and have an image in the clipboard, pressing printscrn on its own will REMOVE that image from the clipboard but not add anything in its place.

If there's any relevant details I have omitted, just say and I'll add more.

Does anyone know what this could be?

Are you able to use the PrtScn/Paste function in MS Paint?

No, sorry - forgot to mention that. This is not a problem that is localised to photoshop.

Since you mentioned that Alt-PrtScn does work, in that it copies the active window to the clipboard, I can only assume that if you have a keyboard which incorporates the F Lock key... that it's enabled when trying to do a PrtScn.

Nope I don't have one... I am on an IBM Model M, doesn't even have a windows key

Thanks for the replies.

The next obvious question is... have you tried a different keyboard?

No, I didn't think I'd need to as alt-printscreen works fine (suggesting there is not something wrong with the keyboard)... :/

iv heard of those ibm model M keyboards. supposed to be built like a rock with little click noises when you type.

Bringing this old topic back up because the problem has just affected me again. It seems like it 'just went away' last time, perhaps after a restart. This would suggest that there's one thing that is causing printscreen to stop working in that capacity... I can still use alt + printscreen for a window capture.

Does anyone have an idea what this could be? I reiterate that my keyboard doesn't have a problem; alt + printscreen works fine.