Yes it will definitely be your HDD. A really good 7200 rpm Drive will help but to really get a noticable difference you want to get an SSD. Can get a 120gb one for about £50-60 I believe.
Also running a free program Called CCleaner will help. Run the cleaning process on that then go to options, start up manager and disable stuff that starts up on boot that you dont need.
I have a 7200 rpm drive on windows 8.1 and my boot takes about 40 seconds. Do not have a dedicated GPU either.
Hope that helps!
i obtain a 7200rpm hdd though one thing i didnt get about ssd- how does it helps? itll help just with what i install on it,youre saying to install windows on it?
Yeah if you install windows on it that would make windows boot ALOT faster. Most people can boot in something like 5-10 seconds. Like a full boot. Also any program you install on the SSD will load faster, be more responsive, files will open faster. Just the general responsiveness and snappiness of windows will be alot better.
So Most people will have Windows along with most used programs and files on an SSD with everything else being on the HDD. Hope that helps.