Run AdwCleaner to remove adware and browser hijackers.
Scan for viruses and other malicious software, such as rootkits for
example.
Use ‘autoruns’ to stop programs from starting up
unnecessarily when Windows starts.
Use CCleaner to remove unnecessary files and clean the registry.
Check the NTFS file system using ‘chkdsk /f’.
Verify the integrity of system files using ‘sfc /scannow’.
Check the state of the hard disk drive, or solid-state drive, using
CrystalDiskInfo.
Review the virtual memory settings.
Switch off search indexing, and possibly install
‘Everything’ instead.
Uninstall OneDrive if the customer never uses it, or at least stop it
constantly synchronising with the cloud.
Consider disabling unnecessary services.
Stop the ‘Superfetch’ service by disabling
‘SysMain’.
Disable the ‘Windows Search’ service.
Also disable the ‘HomeGroupListener’ and
‘HomeGroupProvider’ services.
Turn off ‘fast startup’.
Update any device drivers that are out-of-date (possibly using either
‘Driver Easy’ or ‘Quick Driver Updater’).
Pay special attention to SATA drivers and all others connected with the
hard disk drive or solid-state drive.
Cut down the amount of bandwidth that is dedicated to Windows Update.