You mean without booting from a CD?
If you have a ntoskrnl error at startup , you probably can't get into safemode, only in your bios.
You need a Windows CD to boot from it (change boot order in bios) and run recovery console (R)
You'll need to be a bit familiar with cmd because you'll need to use it to replace a few files (after you back them up of course!) from the C:\Windows\Repair folder to the C\Windows\System 32\Config folder . That worked for me!
If you need help with cmd , I'll provide it.