Hi,
got no time now to verify the following but maybe it might help you:

Windows keeps a list of so called printer-jobs somewhere. I think all print-jobs inited by print-screen are also enqueued there. Otherwise a cuurent print-job, which is initiated by an application like Word etc. might be broken if someone initiates a print-screen.

I read somewhere, that there are Win32-API-Functions for creating, stopping and deleting print-jobs.

I didn't try something like that myself, bt it should be just a suggestion.

Greets

Juergen