Remove failed part by either removing the retaining screw or latch.
Set the part aside.
ENSURE you are grounded.
Remove new part from Anti-Static bag.
Carefully insert the new component into slot or bay.
Secure the part, be careful with screws that go through the component board, too much torque will
crack the board.
Reconnect the cables for the component if there are any.
Check your work, check the adjacent cards, drives, etc. make sure you didn't
inadvertently bump something
loose.
Put case cover back on, this will preclude you from touching any components while the system
is powered up.
Reconnect any external cables you disconnected.
Power up the system.
Watch for system startup screen, if you do not get a screen with in two or three seconds power
the system down, disconnect the power cord.
Something has gone to ground, in other words there is a short between a
component's power connection
and the ground of the power supply.
Once you are certain nothing is loose or you have found the component that is going to ground and
have corrected the problem put the case cover back on and reconnect cables and power it up.