Originally Posted by: KasperowSo going by that logic, it's possible to combine any notes and get different chords based on the notes combined?[/quote]
Yes. It's simply a matter of identifying the intervals between the notes that are played together.

It can get more complex, too! For example, you could name that above chord by reference to any of the notes as the root. Or even a non-chord tone as the root.

For example, this collection of notes together could also be viewed with the G as the root note. Then, it is a matter of identifying the intervals from G to the other notes.

G - root
D - 5th
E - major 6th
F# - major 7th

So, that would be a G (no 3rd) maj 7th add 6th. But, of course, in inversion because the D is the lowest note. So, more precisely:

G (no 3rd) maj 7th add 6th/D

Or you could even name it with reference to a note not present as the root note.

A - non present root
D - 4th
E - 5th
F# - major 6th
G - minor 7th

A (no 3rd) min 7th sus 4th add 6th (no root)

But that starts to get inefficient. :) And so, conceptual efficiency becomes a principle to use. What is the most efficient name for the chord? What gets the point across quickly, clarifying & not confusing the issue of how that group of notes relate to each other?

In this case, it would be the D as root note.

Other considerations are: how does the chord function? For example, what chord comes before it? After it? Do the notes in the chords move from chord to chord in a certain pattern that makes the naming more efficient one way or the other?

Originally Posted by: KasperowAnd on that note, are there any notes that should never be combined?

Yes: ones that you do NOT like the sound of. :)

You can combine any group of notes. Music theory can describe any group of notes you put together. That is one of the primary purposes of music theory: to help you mentally organize & categorize musical sounds & labels. This means you can more quickly recall which sounds you like, which ones you don't & get right to expressing your self confidently with sounds because you know what you are doing. You understand how the notes relate to each other. You know, before you start creating what the result of any given group of notes, or chords will be.
[QUOTE=Kasperow]
I know it may look like I'm asking a lot of stupid questions, but I think it's better to ask stupid questions and get answers than to keep them to myself and never move on because the questions bother me :)

Anyways, thanks for the kind explanations so far :)

Ask anything you want about music! No such thing as an honest question being stupid. Glad you are enjoying this thread. I am, too. :)