Tender

Today the knuckle between the right-forefinger and my hand is very tender, although there is nothing to see or photograph. What made it tender is the computer on the right-hand side of this picture, this arrived yesterday and I installed it today. In the process of installing it I managed to get my knuckle between this computer and the wall, whilst sliding the computer weighing over 20kg into place too rapidly, just in front of the wall. This is the computer that I will be running in place of my original one with a problem, whilst substituting each part in turn, until I find the fault on the original one.