How to Install Windows 10 Technical Preview with VirtualBox

Creating a New Windows 10 Virtual Machine

1. 
   Launch VirtualBox. Locate its icon on the desktop or Programs menu, and double-click on it. This will load VirtualBox on your computer.
2. 
   Name your operating system. Once VirtualBox loads, go ahead and click the 'New' button in the upper left-hand corner of the screen. A little box will pop up with 3 fields inside it. Enter a simple name for the OS, leave the Type section set to it's default, and select Windows 10 (either 32-bit or 64-bit) from the drop-down box to the right of 'Version.' Click 'Next' in the lower right hand corner to continue.
3. 
   Choose your RAM. The next window will have a slider bar on it to select how much RAM to allow the operating system (OS) to use. It is suggested to run no higher than the green area of this bar. Slide the bar to the desired amount. The amount currently selected should be listed in the box to the right of the bar. Something like '2048' measured in MB. When you're finished, click 'Next' to continue.
4. 
   Create a virtual hard drive. There should be 3 options in the window in front of you. The middle one, 'Create a virtual hard drive now,' should be selected by default, but you can choose not to add one by choosing the top option. Creating a virtual hard drive will take up hard drive space on the PC it is being created on; however, this data is not shared with the PC unless specific settings are changed. These settings are not enabled by default. For now, keep the middle option selected and move to the next window by clicking 'Create.'

   1. A series of different options will be on the next window. You will not need to change any of these settings unless you are running some other specific virtualization software. Just click 'Next' to continue.
   2. The next window will ask you to choose which type of hard drive you would like to create, either 'Fixed size' or 'Dynamically allocated.' You can choose either, but the fixed option will make sure that you don't overwhelm your current PC hard drive and will be much faster. Click 'Next' to continue.
   3. On this, the final window, you will need to choose the exact amount of space you would like to give the VM. 32GB is pretty good for a preview OS like Windows 10, but that is up to you. Just make sure that you don't over do it, as adding more space to your VM also takes space away from your real PC. Click the 'Create' button to continue.
   4. Please note that if you choose not to create a virtual hard drive, you will be unable to save any data when using your virtual OS. Also note that the recommended size of the virtual hard drive, for Windows 10, is 32 GB minimum.
5. 
   Wait for the process to finish. After finishing the final part of this step, you will notice that a little box will pop up with a green progress bar inside of it. This is creating the fixed storage with the options you selected. Please wait for this to finish and do not close this window, it will close on its own. Then continue to the next step.
6. 
   Load the Windows 10 ISO file. Now you should see the default VirtualBox window. Right-click the name of the Windows 10 VM you just made, and select 'Settings' from the context menu. A new window will open with several different menus on the left-hand side. Click 'Storage' and you should now see two different boxes to the right of the menu options: 'Storage Tree' and 'Attributes.'

   1. Inside the Storage Tree box, click the item that says 'Empty.' It should be under 'Controller: IDE.' Once selected, click the small disk icon in the Attributes box to the right of 'IDE Secondary Master.' This will drop down a menu. From this, select the one that says 'Choose a virtual CD/DVD disk file…' A new file browser window will open.
   2. Navigate to the folder containing the Windows 10 ISO you downloaded earlier. Select it, and hit the 'Open' button in the lower right-hand corner of the window. Hit 'Okay' to close the Settings window. You will be back at the VirtualBox main menu; click the VM you just made, and click the green arrow to start your new Windows 10 Technical Preview. Make sure to follow the on-screen prompts for installing Windows, and enjoy!