[X-Newbies] Hard drive formatting

[Don]

Hi guys;

I have an old G4 running X.4 on a little 40G hard drive.

To do some playing around, it was partitioned into two
20G pieces to install Linux on one and X.4 on the other.

Step 1:
Started up on different hard drive to prepare the HD.
Did the X.4 install. All is happy.

Step 2:
Kubuntu Linux installed happily.  The HD is now happy.

Step 3: Now I want an entirely different hard drive to
handle another linux flavor.  Attempt to format that
drive.  I mistakenly erased the Linux install.

Step 4:
Went to try to reformat the Linux partition that had
become two partitions during the install, and it would
not allow reformatting 'them' back to being one continuous
empty space in order to let the linux half find what
it wants.

The only way it would allow that would be to also trash
the X.4 install on other hard drive.  :(

So....

Is there any other way to handle it other than just
go the whole way and hose the OSX install also and
completely start over on that drive?

What I'm really looking for is a way that allows
reformatting one or two partitions without hosing
the third one.

Ideas?

Thanks
Don