Analysing Windows 10 slowdown.

[BriAda]

I am not familiar with Windows 10.
I have been asked by someone out here to sort out an unbleievably slow Laptop.
It is particularly slow on startup.
I have had a look using Task Manager and have removed Trusteer Rapport and tried to remove Skype.
Can anybody suggest ways to investigate (from a software angle) a slow laptop?
It has 4GB RAM and a regular harddisk.
I may replace the HDD with a SSD and add RAM although the latter is probably not important.

 

[BriAda]

Many thanks for the various suggestions; installing a SSD seems the favourite and since the most irritating problem is a slow startup time that is what I will try first - using Clonezilla.

What are Metros and will removing them have any negative impact?