I just bought Minecraft but unable to launch

Unable to save download. ms_my.lang
Name: ms_my.lang
URL: http://resources.download.minecraft.net/49/49c3187127b66c9bb456aa38119ae7602c0a219c
Error details: Attempting to move successful download to C:/Users\Dean\AppData\Roaming\.minecraft\assets\objects\49/49c3187127b66c9bb456aa38119ae7602c0a219c
The process cannot access the file because it is being used by another process
Filename on disk: 1c3a-d2bc-2fef-a41a
Path: C:\Users\Dean\AppData\Local\Temp\1c3a-d2bc-2fef-a41a
Exists: file