Yes cause a harddrive will be fast when new, but I'm sorry man but when you jam pack stuff on your pc and use it the harddrive becomes used more, like a car and it's wheels.
When I bought my laptop it was rapid, now well, I can make a bru and come back and it will just be loading.
Yeah,A Deteriating hardrive can cause a loss in performance no matter what brand your hardrive is,maybe run a hardrive test and while it's running listen for abnormal noises.
Try backing up your important data and doing a reformat and reinstall of Windows. That might help the problem and remove your slow boot times. Use this as a last resort because you wont be able to go back once you've done it.
It does not matter what loads at start, does not matter if you defrag it, this is b4 explorer starts, it won't make much of a difference, all I can suggest is you tweak the boot time in computer management.