[rails]作成中のファイルが開けなくなった、vagrant　upも異常

windousの更新後にvirtualboxが開けなくなりvirtualboxやvagrantを再インストールしたり色々やっていたらvagrant　upで異常がでてしまいました。
別の質問も立ていますが自分なりに考えて、gemのバージョンの不具合化と思いsudo gem update を実行してみましたところこのようなエラーがでました。

VagrantはVirtualBox共有フォルダをマウントできませんでしたとなっています。なんでですかね...

<コマンドプロンプト
vagrant up
Bringing machine 'default' up with 'virtualbox' provider...
==> default: Checking if box 'ubuntu/trusty32' is up to date...
==> default: There was a problem while downloading the metadata for your box
==> default: to check for updates. This is not an error, since it is usually due
==> default: to temporary network problems. This is just a warning. The problem
==> default: encountered was:
==> default:
==> default: Could not resolve host: atlas.hashicorp.com
==> default:
==> default: If you want to check for box updates, verify your network connection
==> default: is valid and try again.
==> default: Clearing any previously set forwarded ports...
==> default: Clearing any previously set network interfaces...
==> default: Preparing network interfaces based on configuration...
default: Adapter 1: nat
default: Adapter 2: hostonly
==> default: Forwarding ports...
default: 3000 (guest) => 3000 (host) (adapter 1)
default: 22 (guest) => 2222 (host) (adapter 1)
==> default: Booting VM...
==> default: Waiting for machine to boot. This may take a few minutes...
default: SSH address: 127.0.0.1:2222
default: SSH username: vagrant
default: SSH auth method: private key
default: Warning: Remote connection disconnect. Retrying...
==> default: Machine booted and ready!
[default] GuestAdditions 5.1.16 running --- OK.
==> default: Checking for guest additions in VM...
==> default: Configuring and enabling network interfaces...
==> default: Mounting shared folders...
default: /vagrant => C:/Users/shn/Desktop/work/vagrant
Vagrant was unable to mount VirtualBox shared folders. This is usually
because the filesystem "vboxsf" is not available. This filesystem is
made available via the VirtualBox Guest Additions and kernel module.
Please verify that these guest additions are properly installed in the
guest. This is not a bug in Vagrant and is usually caused by a faulty
Vagrant box. For context, the command attempted was: