Firstly, ensure you PC is placed on a clear, flat surface with plenty of room. You should keep the power lead of the PC plugged into the wall, but with the power switched off. This ensures that there is a route to Earth for any rogue electric charges.

Next, remove the lid from the PC, still ensuring that the power lead is plugged into the wall.

If you have a Tower base unit, like this one, then place the base unit on its side. It is much easier to work this way. Users of desktop PCs to not need to do this.

We would strongly recommend that an Anti-Static Wrist Strap is used. This ensures that there is no electric charge passed to the electronic components that are being removed from the PC, as these will damage the parts and possibly render them unuseable in the future. As can be seen from the picture, one end plugs into a wall socket. The other end goes round the wrist.

Ensuring the wrist strap is worn, undo the retaining screw that secures the component to be removed.

Next, remove the component by pulling both top corners of the card. You may have to be reasonably firm when trying to remove the card.

Lift the card away from the PC - you have removed the hardware.  Place the hardware in an anti-static bag so that it does not become damaged by static electricity.