PROBLEM: You want a checklist of all the tools you'll need for
PC maintenance.

SOLUTION: Whether assembling a new PC or repairing/upgrading
an existing one, keep these items on hand:

-- a flashlight, since you'll probably be plugging cables into the back
   of the chassis one-handed while lying on the floor;
-- assorted flathead and Phillips screwdrivers, three each in small,
   medium, and large sizes;
-- a manila folder for invoices, packing lists, and other notes;
-- a spiral-bound 8.5-by-11 notebook to record everything that
   happens or changes on your PC in the way of errors, bugs,
   upgrades, and repairs;
-- surge suppressors and an uninterruptible power supply;
-- assorted cable ties; and
-- a large plastic box for storing diskettes, CDs, manuals, screws, cables,
   old memory modules, and other loose items.
-- floppy diskettes 3.5" 1.44Mb
 

For a more comprehensive toolkit see
The PC Tool Kit  by "The PC Guide"