Recently my computer has been taking far too much time to boot or shutdown. A couple google searches provided easy solutions which I will provide here.
These are registry edits so understand that a mistake here can disable your computer. Also it is a good idea to back up the registry before you start.
Open HKEY_LOCAL_MACHINE\SYSTEM\CurentControlSet\Control\Session Manager\Memory Management\PrefetchParameters
On the EnablePrefetcher value, change the setting from 3 to 5 (decimal).
Right click on it and select Modify.
Set it a value lower than 2000 (Suggest 200 or 500)