1. Malware - scan your system with Malwarebytes
2. Hard drive is failing - run a diagnostic on the hdd.
3. Low system specs - should have at least a quad core cpu, 8 gb of ram and an SSD.
4. Too many unnecessary programs running around bootup - open task manager, click on start up tab and disable any programs not needed to start.
You didn't list the model number or how old it is. Has it always ran like this or did it just start doing it.