Update your post to include full system hardware specs.
Include PSU: make, model, wattage, age, condition (original to build, new, refurbished, used)?
Disk drive(s): Make, model, capacity, how full?
Does the pc otherwise work/perform normally once booted?
Look in Task Manager > Startup. How many apps and utilities are being launched at startup? Any unexpected or unknown apps or utilities?
Look in Reliability History: Any errors, warnings, or even informational events being captured just before or during boot time?