I don't think i have to download the ISO, boot it up to see your
problem. It's pretty clear you are not well versed with
partitioning. The problem you described here is likely due to the
fact that your HD was singly partitioned previously, hence you had
to delete the windows partition. If your partition is well done,
you would be able to leave the windows partition untouched while
altering your other partitions.
Linux requires the minimum of 2 partitions to install, root
partition and swap partition. In my case, my 40 gigabyte harddisk
is partitioned into 4 sections. 25% for windows, 25% for root, 40%
for home partition, and 10% for swap partition. This way, when i
install a new OS, i simply format the root partition. My windows
partition stays intact, and so is my home partition. Swap is
negligible.
If you had a single partition previously and want to dual boot, you
can choose to either format or split your partitions. Splitting
partitions is not recommended, however, it may be the only choice
in some situations. There are many tools which serves this purpose
on linux, e.g. fdisk, cfdisk or sfdisk. All of these can help you
resize your partition.
Now who's the nut?