well then...
back to the documenting.
document exactly everything you do..
everything.
So im guessing my initial estimation that your pc needs the libusb installed to see the n900 is back on the table and still stands...
perhaps trying another compatible cable (make sure it's compat.) is also another possibility...

BIGGGGG EDIT:

oh gawd...
I do hope what you have on that "n900" (using quotes in a questionable fashion here)...
isn't what htheb just posted...
otherwise you ARE truly screwed dude...
then you got took..rolled...whathaveyou..
caveat emptor...
buy from a reputable ...
a "new" n900 doesn't exist in the market...
except the ones i keep in pristine in my desk drawer...that is...

All things being equal and that vid being comparable to what you got...
then that isn't a proto..
more like a chinese knock-off of a proto...

call it a "prodo" or "pronto" or "toprodo" or anything else you like then ...other than a proto..

n950?
10chars

I bought a new one 2 weeks ago 129€. The only thing, it has no original box and the battery had no hologram sticker but it is a 1430mAh one.
Hardware revision is 2204 and has qwerty layout, original charger, very short original usb cable, different headphones (white from Nokia), no video cable.
I think the ebay seller has still some. When I bought it he sold 6 and 2 were available and now he sold 11 and still 2 are available (selling strategy).

Ebay link.

If they are refurbished, I would say they changed everything because they look and work like new and mine is also the latest hw revision. Maybe they were build up from original spare parts? However then they would be cheap.
Definitely they were not for the german market, maybe some replacement devices for the US market?

Wow, let me first say a BIG THANK YOU to all of you guys, tbh, I didn't expect to get so many answers and help so quickly, so honestly. THANK YOU!!

I can't upload any pics or give details right now, but will be able to do that tomorrow for sure, so expect some pics/details soon and will answer to your questions and suggestions etc..

BUT! From what I've read and seen from your answers, you HtheB may just be right, I think that OS in the video above is what I have on this N900 - so I guess I'm fu***d?

I've paid 30 euro for this phone, so...

I need to go strangle someone right now... be back soon. F**K!!!

Again, thank you so much, I've tried to register here a few days ago but would not let me, the image verification thing was not working so could not register, tried again today and it worked.

Yep. You have a fake N900. Third one I've seen, sadly so.

30 euros...?
not too bad a loss...
still...
and you know who sold it to you?
yeah...
time for my patented shakespearean asides!

pay 'em a visit... (with a bat)
get your money back... (you know what to do..)
I don't advocate violence (ask if he has any lubricant and hand the "nukio m900" back the hard way..)
it is just wrong (make sure you don't trim your fingernails...)

I swear deadpool stole my gig...
bloody 4th-waller..

Oh...
and...
Get a legit n900 scramble...