Open This PC ‘My Computer”.
Right click on Drive C: and click properties.
Click Disk Clean-up.
You will see the dialog box similar to the image second on the right. We suggest you select all items.

Click OK.

This clean-up will delete temporary files, temporary Internet files,
downloaded files and empties your recycle bin.

I recommend running maintenance on each hard drive, including USB backup drives.

(Do Not Run Optimisation "Defrag" on solid state drives)

Once this has completed click the 'Tools' tab at the top of the dialog box.

The top option is Check, click check now, it might say you don't need to scan this drive but I suggest you do anyway.

Another dialog box appears like the
Second Right showing progress of the scan.

The Last Job is to run the Analyse / Optimization “Defrag tool”.
This routine checks for fragmented files and reunites them in the same or close together clusters to make disk
access that little bit faster.

Click Optimize, select all drives You have the option to click the Analyse button to see if you hard disk does need defragmenting.

Select all drives and click analyse, when finished analysing,
you’ll see how fragmented each drive is, any drives that are above 3%, select them and click Optimize.

System Reserved often reports that it’s fragmented, don’t
Worry about this, it’s a very small partition.