I've built and repaired PC's for about 12 years now. What's most likely happening at start-up is Windows is trying to sift through all the useless processes and crap installed on your PC.
The best thing for a fast PC is to not install a bunch of garbage on it. Especially your DAW machine. I don't install screensavers, or flashy things that alter the OS in some way. I don't go online with my DAW machine so I don't use any anti-virus (major resource hog). I don't download any updates from windows either, unless there is a specific update for a problem I'm having (which hasn't ever happened). They are always just security updates, and whenever I install any of them, my memory usage goes up. I also disable all updates, notifications and any services that aren't necessity for Win to run. I also NEVER let anyone on my DAW machine. No exceptions. The less processes and updates you have, the better your machine is going to run. If you hit Ctrl-Alt-Del or even better, hold shift-control with your thumb and hit esc with your index finger it skips the log screen and takes you right to the task manager. If you have 60 or more processes running after you hit show processes from all users, you have way to much crap on you PC. .After your PC warms up and is idle (no hd light flashing or anything) your CPU usage should be 0%. With 8 GB of memory, your physical memory be at around 8-10%. I have 4GB and at idle I have 0 cpu and use about 14% physical memory.
Even if you buy a PC new from a retailer. They all come loaded with garbage. Removing useless progs from your PC will help, but there's nothing like a fresh clean install of Windows minus the garbage. The key is to resist installing things you don't really need.
I have an older dual core amd with 4 GB memory on Win 7 Ultimate, and I can start playing a song in sonar in under 2 minutes from the time I hit the start button on my tower. If you can, you'd be better off to use a cheap pc or laptop for internet and stuff and try to keep your DAW machine free of unnecessary software.