I hope that Michael has been doing some weight training if hes still going to be treating his PC like a laptop and taking it around to his mates all the time
Remove all the PCI and GFX cards and disconnect all the wires from the mobo taking careful note of the cluster of wires at the botom end of the mobo that go to the front panel for the power and reset switches and any front USB and/or audio connectors, as the wires may be a little different on the new case.
Undo the screws fastening the mobo to the case and lift it away and carefully place the mobo where it cant be be damaged, I usually have the underneath part facing upwards so nothing can get shorted out ,in case theres any residual static hanging about.
Check the positioning of the small brass screw in inserts that are in the old case that the mobo fastened to.
Arrange the brass inserts in the new case in the same layout.
At the rear of the old case where the mouse and keyboard connect theres a rectangular plate that you need to remove by pushing it inwards, they can be quite tight.
These are motherboard specific and you will need this plate fitting in the new case to take your mobo.
Once you have fitted that plate to the new case and made sure that the brass inserts are all in the correct place, if they are already screwed into the case make sure that there arent too many as any extra could touch a part of the mobo and short it out, you may even have to use some of the brass inserts from your old case as some manufacturers dont supply enough.
When fitting the mobo to the new case you need to align it with the rectangular plate that you removed from the old case.
This can be a little awkward as there are springy metal clips that push againt the mobo as you place it in position.
It may be handy for you to be holding the mobo in the correct place and have Michael put a couple of screws in.
Dont fully tighten the screws until you have got them all in as sometimes you need a little movement.
Once they are all in tighten them but remember you are only using small screws and they are going into brass so you dont need the strength of a gorilla to tighten them
The rest is simply a case of refitting everything and connecting the wires, taking note of the front of case wires as they may be labelled a little differently to the old ones.