Hi Ajneale,
Microsoft has released Windows 10 preview. please visit
http://windows.microsoft.com/en-us/windows/preview-iso for more info about Windows Technical Preview.
Please follow the steps as suggested below :
1. Initiate the installation through the Windows 10 preview .iso file :
http://kb.parallels.com/4729
2. Locate it manually, which will display as "Unable to detect OS".
3. Just ignore it and click on "Continue" anyways.
4. Now select the Windows OS type -> More Windows -> Other Windows.
5. If selecting Windows 8 or Windows 7 will terminate the installation.
Once Windows 10 OS is officially launched, it will be added to the list of operating system.
Click to expand...