|You need to explain a little more as to what you are trying to do as your question doesn't make sense at all.|
A DLL is a Dynamic Link Library. A type of file that resides on your had disk and is loaded by the operating system automatically as required. Its contents and functions are invisible to the user.
The Kernel is the core of the Operating System. The bit that is always present in memory and may well consist of some DLLs.
Rebooting a system is something you do every day when you switch it on.
Are you asking about reinstalling the Operating System?