The Advanced Startup Options menu in Windows 8 is the central fix-it location for the entire operating system.

From here you can access Windows 8 diagnostic and repair tools like Refresh Your PC, Reset Your PC, System Restore, Command Prompt, and much more.

Advanced Startup Options is also where you access Startup Settings, the menu that includes Safe Mode, among other startup methods that could help you access Windows 8 if its having problems starting.

The Advanced Startup Options menu should appear automatically after two consecutive startup errors. However, if you need to open it manually, there are six different ways to do so.

The best way to decide which method to use to open Advanced Startup Options is to base your decision on what level of access you have to Windows 8 right now:

If Windows 8 starts normally: Use any method, but 1, 2, or 3 will be easiest.

If Windows 8 does not start: Use method 4, 5, or 6. Method 1 will also work if you can at least get to the Windows 8 logon screen.

Difficulty: Easy

Time Required: Accessing Advanced Startup Options can take anywhere from a few seconds, to a few minutes, depending on which method you use.

Applies To: All of these means of getting to the Advanced Startup Option menu works equally well in any edition of Windows 8 or Windows 8.1.

Method 1: SHIFT + Restart

Hold down either SHIFT key while tapping or clicking on Restart, available from any Power icon.

Tip: Power icons are available in Windows 8 from either the Settings charm or from the logon/lock screen.

Note: This method does not seem to work with the on-screen keyboard. You'll need to have a physical keyboard connected to your computer or device to open the Advanced Startup Options menu this way.
Wait while the Advanced Startup Options menu opens.
Method 2: PC Settings

Swipe from the right to open the charms bar.

Tip: If you have a keyboard, use WIN+I and then skip to Step 3.
Tap or click on Settings.
Tap or click on Change PC settings at the bottom of the charms bar.
Choose Update and recovery from the list of options on the left of the PC settings window.

Note: Prior to Windows 8.1, choose General instead and then skip to Step 6.
Choose Recovery.
Locate Advanced startup, at the bottom of the list of options on your right.
Tap or click on Restart now.
Wait through the Please wait message until Advanced Startup Options opens.
Method 3: Shutdown Command

Open Command Prompt in Windows 8.

Tip: Another option is to open Run if you can't get Command Prompt started for some reason.
Execute the shutdown command in the following way:
shutdown /r /o

Note: Save any open files before executing this command or you'll lose any changes you've made since your last save.
To the You're about to be signed off message that appears a few seconds later, tap or click on the Close button.
After several seconds, during which nothing seems to be happening, Windows 8 will then close and you'll see a Please wait message.
Wait just a few seconds more until the Advanced Startup Options menu opens.
Method 4: Boot From Your Windows 8 Installation Media

Insert a Windows 8 DVD, or a flash drive with the Windows 8 installation files on it, into your computer.

Tip: You can borrow someone else's Windows 8 disc or other media if you need to. You're not installing or reinstalling Windows 8, you're just accessing Advanced Startup Options - no product key or license breaking required.
Boot from the disc or boot from the USB device, whatever your situation calls for.
From the Windows Setup screen, tap or click on Next.
Tap or click on the Repair your computer link at the bottom of the window.
Advanced Startup Options will start, almost immediately.
Method 5: Boot From a Windows 8 Recovery Drive

Insert your Windows 8 Recovery Drive into a free USB port.

Tip: Don't worry if you weren't proactive and never got around to creating a Recovery Drive. If you have another computer with Windows 8, or a friend with Windows 8 on his or her computer, see How To Create a Windows 8 Recovery Drive for instructions.
Boot your computer from the flash drive.
On the Choose your keyboard layout screen, tap or click on US or whatever keyboard layout you'd like to use.
Advanced Startup Options will begin instantly.
Method 6: Boot Directly to Advanced Startup Options

Start or restart your computer or device.
Choose the boot option for System Recovery, Advanced Startup, Recovery, etc.

Note: What this boot option is called is configurable by your hardware maker so the options I mentioned are just some that I've seen or heard. Whatever the name, it should be clear that what you're about to do is boot to Windows 8's advanced recovery features.

Important: The ability to boot directly to Advanced Startup Options isn't one that's available with a traditional BIOS. Your computer will need to support UEFI and then also be configured properly to boot directly to the ASO menu.
Wait for Advanced Startup Options to begin.
What About F8 and SHIFT+F8?

Neither F8 nor SHIFT+F8 are reliable options for booting to the Advanced Startup Options menu. See How To Start Windows 8 in Safe Mode for more on this.

If you need to access Advanced Startup Options, you can do so with any of the several methods listed above.

How To Exit Advanced Startup Options

Whenever you're finished using the Advanced Startup Options menu, you can choose Continue to restart your computer, booting you back into Windows 8... assuming it's working properly now.

Your other option is to choose Turn off your PC, which will do just that.