One of the first problems that a Windows 8 user has is….
“How can I boot in Safe Mode… the classic F8 is not working….” 

The easiest way is: 

1. Press Windows Button and write msconfig, and Enter: 

2. Go to Boot Tab, and select Safe Boot:

*Other info:
Minimal is the normal safe mode.
Alternate Shell is a safe mode with command prompt console
Network is a safe mode with network

3. Restart

4. After reboot you will be in safe mode. Do your work ^_^

5. After you finished you have to go back to msconfig ( step 2 ) and un-check safe mode, and then restart:

*If you do not do this step after reboot you will be again in safe mode !

Enjoy !