Spare Components :

Screws -Screws for closing the case, mounting the computer components inside the case etc. I tend to have screws left after each computer I build from parts, so I keep them in my toolbox for jobs such as adding hard disk drives and other computer upgrades.

Washers - also known as spacers, should be fitted between the case and the motherboard. They insulate the board from the computer case. Keep a few handy in your toolbox.

Spacers - generally performing the same function as the washers (above), spacer screws insulate the motherboard from the computer case, and also offset the board the to the required position.