More info on your HDD might be found in Device Manager, but more important click on Computer to see how much free space you have left on it. Look at transferring some of its content to an external drive regardless plus I would just use Windows Defender as some have said above. I would guess that your current 1TB drive is a HDD, maybe a bit of maintenance on it might help if not done recently - i.e., the inbuilt disk clean/defragment tools and maybe consider using the free version of Ccleaner to check for any registry entries that need fixing.

Last 2 I have bought from Valucomputers.co.uk. Refurbished but still come with a warranty. Not a mark on mine, looked like new but price wan't like new