I opened the launcher, and tried to download minecraft bedrock preview. 

it showed some pop up windows about where it will install, and from then it started downloading, but now it has stopped at 2.86 MB downloaded, and I can't do anything with it. 

I tried shutting it down from the task manager, and then I even restarted my PC but it has remained the same, and I can't play anything else from the launcher, nor I can pause or stop the installation process. 

Thanks for any and all help.