Hi Ed, 
Just a note to say how grateful Elizabeth and I are for the work you did last Friday in restoring our desktop computer to full health. We were so impressed by your technical expertise and by the speed with which you carried out your work. It was a pleasure to have you in our home, and on a personal level, we both very much enjoyed meeting you. We will always call on you for any IT concerns which may arise in the future. 
Thanks once again, 
best wishes, 
from Richard and Elizabeth H