Possible Duplicate:
How do I boot Windows 8 into Safe Mode?
Windows 8 contains a special bootloader which doesn't recognize the F8 hotkey according to this and this:
On Microsoft's MSDN blog, the company has revealed in great detail some of the changes we can expect to see to boot options inherent in Windows 8. Most notably, gone are the days of tapping F8 repeatedly.
So, how do we access safe mode now?