if computer run slow down, it is time do the service, replace new hard disk, install new OS , our repair charge is from £99
For iMac 21 / 27 inch Retina
from late 2012 to 2020
To fix a slowdown problem, freezing, not loading, crush etc, it may need do the service and replace new SSD hard disk, install OS, repair cost is form £199 depon on the size of the SSD.