You have two way to install new DCS 2.0 version:
Install 2.0 from the official, so you will obtain a second installation of DCS separated from DCS 1.5
Executing DCS_updater.exe from "\Eagle Dynamics\DCS World\bin directory of DCS 1.5 in this way:
“C:\Eagle Dynamics\DCS World\bin\DCS_updater.exe” update openalpha:2.0
DCS 1.5 will be lost and substituted by DCS 2.0
P.S. I select way n.2 
I’m installing according to option 1 right now, only a couple more gigs to download/install. 
Uh, seems like I don’t have any terrain in my DCS 2.0, so no flying after an hour of downloading. I’m not too keen on spending $50 just to get somewhere to fly, so…
Ah well, bedtime for me now, but if I choose to install according to option 2, will I have any terrains to fly over?
Sorry Mikke to play with DCS 2.0 you must buy NTTR map, i discover at the end of download. Sorry my fault i did not reporter you this.
You should still have DCS 1.5 installed on your PC is it true? I hope that…
Sorry Mikke to play with DCS 2.0 you must buy NTTR map, i discover at the end of download. Sorry my fault i did not reporter you this.
You should still have DCS 1.5 installed on your PC is it true? I hope that, tell me yes.
Sorry Mikke to play with DCS 2.0 you must buy NTTR map, i discover that at the end of download. Sorry my fault i did not reporter you this.
You should still have DCS 1.5 installed on your PC is it true? I hope that, tell me yes!
Yes, as I said, I installed it in the first way, so I still have my old DCS installed as well.
Do you mean that you now lack terrain (unless you bought the NTTR map)? :o
I must say I think it’s more then just a bit funny that they distribute 2.0 without any map at all, not even a flat “this is the ground”…
A quick search later tells me that it should be possible to download the NTTR map, so perhaps no $50 needed after all? Will test when I get home and have a chance to try it.
Didn’t know the alpha public 2.0 release was only the Nevada map for now.
I would suggest then the beta 1.5 That’s the one with the free improved Blacksea map and not only that. It had already some fixes and it looks stable. Worth a try Mikke 
Downloaded and installed the Nevada map, a lot of gigs, but it’s there now. But guess what, it wants an activation code! :anpaper:
Well, maybe I should try 1.5 instead…
From Eagle Dynamics
“Over the past two weeks, we have seen a lot of questions regarding how to download and install the Nevada map, for those that purchased it or got it free as part of the A-10C Beta program. For those that missed the answers on our forums, here is a review.
If you purchased the map through our e-shop at: http://www.digitalcombatsimulator.com/en/shop/terrains/
Install DCS World 2.0 and open the Module Manager. Please look in your Available DLC / Terrain page for the listing of the map with an install button next to it. If you do not see it, please run Repair DCS World 2.0 Open Alpha from your Windows Start Menu / All Apps / Eagle Dynamics and then look again.
If you believe you purchased the A-10C Beta prior to February 21st, 2011, please visit the Nevada DLC map store page at: http://www.digitalcombatsimulator.com/en/shop/terrains/nttr_terrain/
On this page, you will see a button entitled SHOW SERIAL NUMBERS. Please press this button for your free key.”
Have a great weekend,
The Eagle Dynamics Team
Looks like you have to purchase it Mikke…
Yes, that was my conclusion, you have to buy it to get it.
I installed 1.5 beta instead, no Nevada map, just the old one, but that I can fly on.