When starting up my PC I get a blue screen with an error message stating that the file \windows\system32\winload.exe is missing or contains errors. The error code is 0xc000000f. It is asking me to insert the installation media, however I don't have this as I have upgraded to Windows 10 online.
Furthermore, I have noticed a severe decline in performance since Windows automatically updated 4 days ago. It now takes hours to start up my computer whilst this used to take 1-2 minutes (updates of 8 October 2015).
How can I get Windows 10 working again?
Your help is much appreciated!