Hi!

My problem is that I'm not really clear about the
specifications for the cable connectors. I see all sorts of
descriptions on various web pages:

Let's see if we can't break this down and make it a little easier.

The "Molex connectors" you see discussed are the larger ones that have four
holes in them. They are so named because Molex is the company who developed
them (AFAIK). As you've seen in your computer, these usually plug into
devices like hard disks, CD-ROM drives and some older floppy diskette
drives. You'll have between four and six of these, and maybe more or less in
some exceptional cases.

The smaller rectangular four wire connectors are used for physically smaller
drives, such as your 3.5" floppy drive. Some internal Zip drives use these.
There are probably only two of these.

As for powering the motherboard, you usually have two major groups of plugs,
at least that I'm aware of.

The first is a long rectangular plug that fits into a matching socket on the
motherboard. This is the so-called "ATX plug". It is responsible for
providing power to the motherboard. There is only one of these.

The next plug is a four pin square. This plug has two rows of two pins each.
It is used to power the CPU core on most motherboards. There's only one of
these as well. It has all yellow and black wires going to it.

Other plugs:

The so-called SATA-plugs are long and very thing rectangular plugs often
filled with little edge-connect pins. They're usually made of black plastic
at one end.

Your current power supply may have a few other wires coming out of it that
aren't connected to anything at all. The ones that look like the "Molex
plugs" or anything described above are usually for future expansion. (Don't
be too surprised if you have extras--I've seen PC power supplies that had
many more of these than could ever be used. I've also seen some with far too
few for the case they were installed in.)

Other plugs that don't fit any description above are probably just not used
in your computer, and needn't be hooked up.

Your best bet (if you don't mind shopping locally) if you're not sure what
to buy is to head into a computer shop where the people know what they're up
to and take your old supply with you. They'll know what you need and can
explain things if you have questions about the plugs.

William