Most reasons why a PC starts up slow, is that it is loading too many start-up programs.
Check task manager under startup, services.msc, msconfig.,
Before turning off anything make a system restore point. Research what the startup is if you do not know or if you are not sure.
Make sure it is not needed to startup before disabling it. Always look within the software first if there is a way to turn it off, before using task manager startup items, services.msc or msconfig.
True these programs do it for you when not familiar with what you are doing, but can make a mess for you. Just saying most of those speed up your PC programs are things you can do yourself once you know how.