OS Startup Issue

Sometimes when I startup my computer (notice this isn’t happening every time) The system will take a long time to start and spends a lot of time on the blue screen between the Windows logo and the logon window. When the OS loads I’m missing the Aero theme and it tells me that the Windows audio service failed to load. When I try and restart this service, it will not let me and I end up having to force shut down my system and continue rebooting until the OS loads normally. There is no rhyme or reason as to when this happens and I’m stumped on how to fix it.