Difference between a cold and warm reboot
Cold Reboot is where you turn the computer completely off so there is no power to the system. This would be the same result as if you pulled the power cord from the system. This happens when you click Turn off computer and then click Turn off.
Warm reboot is where you restart windows and it goes back into windows. This happens when you click Turn off computer, and then click Restart. Power never goes off on a warm reboot like the cold reboot does.
The advantage of Cold reboot is that it releases anything that is stuck in memory. If you are getting error messages or other issues, it might be because something is stuck in memory. When you do a cold reboot, it clears the memory. A warm reboot doesn't release items stuck in memory. Only a cold reboot does.
The only thing a warm reboot does is for installing software. Software sometimes requires modification of a system file. The system file cannot be altered if it is in use, the install program will update it when you restart (warm boot) the computer. When it reboots the system file is not in use and is able to be updated.