Yes, you're being very unclear.
Please post the output of "fdsik -l /dev/hda" and "fdisk -l /dev/hdb", assuming hda and hdb are the two only hard disks you have (otherwise, post the output of "fdisk -l /dev/hdX" for all X corresponding to hard disks). Also, please restate your question
word by word, except that you always refer to disks by hd<letter>, and partitions by hd<letter><number>. I assume you don't have other GNU/Linux distros installed--correctly?
Also, there is no such thing as "formatting windows". What you probably mean is "formatting the partitions on which windows resides".
Also, there is no such thing as a "grub partition". There is the "/boot partition", which is the partition you choose to mount at /boot, and that one is typically used for storing grub.conf (or menu.lst, or whatever you kids call config files these days
) and other things. Then there's "the partition in which boot sector grub is installed", which might be what you mean.
Also also ("... with"
), I don't think you mean "windows machine"--probably what you mean is "windows installation" (or, in a wider context: "lose the ability to boot (or run) windows").
One thing I
can say: if you "wipe" both partitions on the main disk (assuming wipe means either delete or format), they will
not magically merge together into one. If you delete them, though, you can create a new one taking up the space previously taken up by the two deleted partitions (assuming they're adjacent), but you'll of course lose all data on them.
I don't mean to bark at you, but I just find it hard to decipher what it is you mean. I'll gladly help you, if you are a little more careful in explaining the issue. Please read "how to report bugs effectively", by Simon Tatham (IIRC). Google is your friend.
