Please read this and provide the necessary information: http://feedback.arma3.com/how-to-user.html.html

To solve your problem we need dxdiag and files from this folder: "C:\Users\<Name>\AppData\Local\Arma 3 Alpha\"

Can you pack the files in winrar and upload it somewhere please?
When the *.rar will be smaller than 2.097k, you can attach it here. Thank you.

When reporting please refer to "how to guide" http://feedback.arma3.com/how-to-user.html.html

Closing due to lack of info / response.

If the issue is still reproducable for you, please create a ticket for it.