FYI: For those who are still getting the slow shutdown/restart/reboot problem, and are concerned, and who are comfortable using the EVENT VIEWER, it might be useful to look at the following sub-tree called Diagnostics-Performance.
The event Viewer is located under Windows Administrative Tools inside the start menu, but you can type that in the search icon.
If you expand the tree view on the left (By clicking the chevron so it points downwards) , under Applications and Service Logs, then expand Microsoft, then scroll down until you see Diagnostics-Performance, you can click on the "operational" item in there, and you should see 200 - 300 or so event items appear in the central display part of the UI.
Here you will find Event ID's 100, 101,103,108, 200 and 203 typically, but you may find more ID's depending on the items that are detectedthat have slowed down your shutdown or boot startup.
If you find that (for instance) you have 2 Anti-Virus products active together, that might cause some interaction and slowness**,**or it might be one of those McAfee scanners that get into Flash updates if you do not remember to untick the "optional download". If there are ANY items that you KNOW you added yourself, but you don't need them for anything important, and they can be safely uninstalled, then check that out. There may be many system critical items logged, for instance Crypt services, or Licencing Services (ClipSVC), so obviously those types of things you CANNOT do without!
If there are any unusual or unexpected items there, do NOT take any actions until you have thoroughly researched them and checked on legitimate Microsoft and other trusted vendor sources before uninstalling or trying to disable anything. If you DO find a legitimate add-in program or service that YOU installed, and it is listed in the Critical Events at this section, check with the software vendor, or if it is a Driver Service (e.g. audiosrv, audioendpointbuilder in the Warnings Events 103) then check your PC/Laptop vendor web-site for updated driver software.
NOTE: I would recommend taking at least a "Restore Point" (or preferably a full backup or system image) before doing ANY significant changes.
HINT: Do NOT do too many changes all at once, best to do test reboots between changes, re-check the event logs.