1) Is the PSU enough for this build or do i need to get a 850 for when i go crossfire HD7970(in a month or 2) ?
2) Am i allowed to buy the OEM licensed version of windows 7 or do i need to buy the more expensive one ?
3) Do i need to get a different CPU cooler or is the stock cooler good enough ?
4) Is the case big enough?
5) first time builder so just wondering is there anything extra that i need to buy?
I'm not sure whether i should get the HD7970 or the HD7950 since its a €100 difference
so i am wondering is the €100 more on the HD7970 worth it over the HD7950?
i dont plan on overclocking so should i get the normal 2600?
and would it be possible to add a second 7950 gpu(in a couple of months) and put em in crossfire?
As easy as it is to over clock these days I would spend just a few more Euro's and get the 2600K. You never know when you might want to give it a try. Big gain for little effort and not much more money.
That board and psu will allow you to run dual cards @ 8x so your good to go if you ever want to add another one of those cards later on.
That's a tough call. I like the after market cooling much better than the stock cooling, but 30 Euro's...that's some money. If you have the extra money...that is a nice cooling set up on that card.
As for that case...it has plenty of room. That's a big case, what that case does lack is extra case fans. That case allows you to add 200mm, 140mm, and 120mm case fans to it giving you a much better airflow (cooler temps).