So I wanted to try out some "new technologies" as Docker and Vagrant, so I decided to install Vagrant on my Windows 7 machine. It turned out to be not that "just install and go" as written down in the tutorial.

So, the short version to get you up and running:
1.) Install VirtualBox VirtualBox-4.3.12-93733-Win
Yes, 4.3.16 is current, no - you can't use something higher than 4.3.12 because of an error with ssh...
2.) Install some software which comes with ssh
So if you haven't installed git until, that should be the perfect time to do that.
Oh, and please include the bin folder with the ssh.exe in the PATH Variable of your Windows machine. Vagrant needs to call it to connect to your "VM".
3.) Install Vagrant 1.6.5
4.) After doing all that, you should reboot your pc.

Your first vagrant session:
1.) Open up your CLI / cmd.exe
2.) Create an new folder and enter it
3.) Init vagrant, i.e.
vagrant init
4.) Start the vagrant vm
vagrant up

After all that, you will be able to connect to your VM with:
vagrant ssh

If you want to stop your machine, enter
vagrant destory

And that is it.
Oh, by the way: Vagrant may use VMWare Workstation instead of Oracles Virtual Box - if you're willing to pay 79 Bucks per PC...