I just bought Minecraft but unable to launch

Unable to save download. nn_no.lang
Name: nn_no.lang
URL: http://resources.download.minecraft.net/50/500715127be36cfa90c67e55aed34470f3882e7d
Error details: Attempting to move successful download to C:/Users\Dean\AppData\Roaming\.minecraft\assets\objects\50/500715127be36cfa90c67e55aed34470f3882e7d
The process cannot access the file because it is being used by another process
Filename on disk: 24f0-6305-41ef-3857
Path: C:\Users\Dean\AppData\Local\Temp\24f0-6305-41ef-3857
Exists: file