I assume that's the little one. Assuming you want to preserve the data
that's on these drives, you're going to need a third-party tool to do
what you need to do. Partition Magic (www.powerquest.com) is a very
good one, there are others. With such a tool you'll be able to combine
existing partitions and switch them from FAT16 (which I presume they
are using, since none are bigger than 2GB) to FAT32.

Yes.

You cannot combine partitions with any Windows tools - you need a
third-party utility such as Partition Magic (very good, but expensive) or
BootitNG or Partition Resizer. Your procedure would be to first convert and
combine E and F. You will do this by removing the F partition, converting E
to FAT32, then expanding it into the space that F used, so there is no need
to convert F to FAT32.

I would recommend that you then copy everything from D to E, remove the D
partition, move the start of the extended partition (the container for the
logical drive) up to the start of the new D (the old E), then convert and
expand the C partition up to the same point. This will give you a C
partition of about 4Gb and the rest in D. It looks a bit like this:
CCCCDDDDEEEEF
CCCCCCCCDDDDD
An intermediate option (eg, about 3Gb in each) would work as well.

The reason for this arrangement is that I am guessing that you have a lot of
references in your system to files on D, and much less references to files
on E.  By copying the current contents of D to the new second partition, and
keeping two partitions, the internal refrences to files on D will remain
correct.  If you have references to files on E you will have to fix these as
you find them.

You should run Scandisk to ensure that the file system is OK before making
any changes. Do it from within Windows, and also from a boot to DOS to
ensure that all errors are found.
--
Jeff Richards
MS MVP W95/W98