In Windows 8, when you type in your login credentials, you will be presented with the new Metro interface Start Screen as shown below.

In order to get to the desktop in Windows 8, you have to click on the Desktop tile. This is really not a big deal for me, but a lot of friends I know hate this. They wanted to find a way to boot Windows 8 directly to the desktop and bypass the Start Screen altogether. Well, there is a way to do that luckily.
Unfortunately, it requires a registry hack. In this article, I will show you how to change Windows 8 so that it will start up with the desktop rather than the start screen. The only issue with this method is that the start screen still pops up for about a second or two and then the desktop appears. So far no one has found a clean way to actually go straight to the desktop without the start screen appearing at all. If you have or know of a way, feel free to post a comment here!
To get started, go to the Start Screen and right-click on any empty space other than a tile. You’ll see the All apps link appear at the bottom.

Next, scroll to the right and click on Run under Windows System.

Type in regedit into the Run dialog box and click OK.

Now navigate to the following registry key:
HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\Current Version\Winlogin

On the right hand side you’ll see a key called Shell. By default, it is set to explorer.exe. You have to change this to either of the following:
1. C:\Windows\explorer.exe, explorer.exe
or
2. explorer.exe /select,explorer.exe
That’s it. Now exit the registry and restart your computer. When you log into Windows 8, it should show the Start Screen for about a second and then switch to the desktop. It may also open a Windows Explorer dialog also. So if you really hate having to click on Desktop from the Start Screen, this is the best way so far to do it. Enjoy!