Is there a way to restart without shutting down first on Windows? On Linux this is possible using kexec and serves to minimize downtime. What happens is that one does not pass through the bootloader stage and no BIOS is seen.
I do not believe it is possible. As Moab pointed out in the comments, it used to be possible in Windows 9x.
That used to work by unloading Windows, going to the DOS environment, and reloading Windows again (if I recall correctly, one could simply type in
Disclosure: I wrote ShutOff 2000, so I've been fiddling around with ways to shut down Windows since 1999. I don't claim to know all there is about it, though.
In Windows 7 • Open the Start menu. • Hold down the Control and Shift keys, and right-click on a blank space in the Start menu. • Choose "Exit Explorer." • Open the Task Manager (Ctrl+Shift+Esc), navigate to File->Run, enter "explorer" and hit OK.
In Windows 8, Shift Ctrl Right Click at the extreme left of the taskbar - everything else is the same as 7.
BTW I mainly use this when an icon that I want on the taskbar (like skype) fails to appear. Closing and restarting explorer will always fix it.