Hey Matt and hey MusicStudent,
@ Matt: I'll check that out, thanks!
@ Music Student: Yeah, there are other programs which do that, including music apps; Rocksmith does it, for example; I think Sythesia also did it, and I know that Synthesia is planning to do it (again), since it's just quite unconvenient for the users otherwise. In regard to the Windows options: I have already checked them out, but didn't find any options for specific applications (just in general - and in general, I do want my computer to go into sleep); but maybe it's just me (I'm really not very good in understanding operating systems).