Well, I didn’t buy W8, and am not using it, but there are folks here who do so, “This Bud’s for you!”.

One of W8’s features is an amazingly rapid boot. Actually, it’s a “hybrid boot”: a cross between hibernation and booting.

But, let’s say you’re having a problem which you need “Safe Mode” to solve. How can you do it in such a rapidly booting environment? F2 and F8 time periods are reduced to really tiny periods. According to the MSDN blog, “the interval wherein Windows waits for F8 interrupt is reduced to less than 200 milliseconds and thus, the chances of it detecting the F8 interrupt is extremely low.” So, part of the “magic” was effectively sacrificing the legacy F2 and F8 interrupt period. Magic indeed.

So, one way is using the “Advanced Boot Options”. The Boot Menu contains options for:

1. Loading another operating system
2. Troubleshooting
3. Turn off the PC
4. Use a network device for booting

If you click on “Troubleshoot” you are given more options:

1. Use System Restore
2. Use System Imaging
3. BIOS Access
4. Automatic Repair option – helps you diagnose and fix problems automatically
5. Command Prompt and
6. Windows Startup Settings – helps you change the startup settings (enable/disable debugging mode, enable/disable boot logging, enable safe mode etc options are present under this group)

So, how do you get to the boot menu?

1. The first method is to get it through the PC Settings dialog box. The PC Settings charm is available under Settings. Open the PC Settings and in the dialog box, click on General and select Restart Now under Advanced Startup.
2. The second method is easier. Press SHIFT key when you click on Restart. This will shut down the computer and restart it to present you the Boot Menu.

Forget about the third way. You’ll never remember it.

But…I have an easier way brought to you by The Windows Club (good folks there!). You just have to re-enable your F8 key.

To re-enable it (it’s a legacy key/function) use the above to get to “Troubleshoot” and choose option 5 (Command Prompt).

Type in the following (without the quote marks):

“bcdedit /set {default} bootmenupolicy legacy”

and hit Enter.

You will see the message: The operation completed successfully.

To reverse it, go to the command prompt and type:

“bcdedit /set {default} bootmenupolicy standard”

and hit Enter.

Getting your F8 key back will cost you a few seconds during the boot, but it might be worth it if you need to troubleshoot things frequently.

Source:

http://www.thewindowsclub.com/safe-mode-in-windows-8