Microsoft has confirmed that Windows 10 will be sent out via a staggered release and it might take months for all countries to be able to download it for their PC and tablet. Obviously you want to get this right away and I have found a way to force your computer or tablet to download Windows 10, bypassing any restriction that Microsoft has enforced for your device.
First of all you want to opt into the Get Windows 10 program. For the last few months a little icon has been on your notification bar and you are basically telling Microsoft you want to download it as soon as its available.
Next you want to make sure your computer is setup for automatic updates. You get to this screen while in your Control Panel. When you are in the control panel you can simply copy/paste this link Control Panel\All Control Panel Items\Windows Update\Change settings
In order to force Windows 10 to download to your Microsoft Surface tablet or your PC you need to delete everything found in the C:\Windows\SoftwareDistribution\Download directory. This will NOT adversely effect your computer and is critical for this force download system to work.
Once you have deleted everything in this folder you want to hit the Windows Button and launch your Command Prompt. I recommend launching it as Administrator. Once you are there type in wuauclt.exe /updatenow
The final step is to now search for updates using the Windows Update Tool and it should automatically start downloading Windows 10 your computer or Windows 8 tablet.
Microsoft has said that US customers are getting priority to download the full and complete version of Windows 10 first. Australia, Canada, the United Kingdom and other countries should be getting it in the next week. Tablets running Windows 7 or Windows 8 are the last ones to receive the update, but if you do all of the above steps you are basically forcing Microsoft to serve you the next available download! I did this on my end in Canada and it worked.