Missing HDD space after bootcamp erased the Windows partition!!!

Hi there.
This s my first post...for unfortunate reasons...!
Everything was going fine...to what it matters, i "had" a Macbook Pro 2.6 with 4 Gbs memory and with 2 partitions:

- One with Leopard 10.5
- Other with Windows XP (created with Bootcamp)

For work reasons, i had to erase both partitions and reinstall them...i started with Windows.
As i known before and not now, there are 2 ways(amongst many) to "safely" remove a partition:

- Bootcamp Assistant
- Disk Utility

As i have created the windows partition with Bootcamp, i choosed the bootcamp assistant to do the job(instead of the Disk Utility)...BIG MISTAKE!!!
The Bootcamp Assistant only had a single option, which was like "create or erase Windows partition" as far as i could remember...
So i clicked it...then choosed the volume/partition which i wanted to remove, named "Windows" (as i had the OS X 10.5 installed in the other partition)
It took like 1.5 sec to erase 70 Gbs and in the moment i´ve found it very strange...
Next thing i know...my "70-Gbs-Windows-Partition" is missing for three days!!!
I´ve tried Disk Utility(checking the drive and repairing it with First Aid),Ubuntu(booted from it to find the missing partition),Whatsize, Bootcamp(again, because i´ve read about a user who could restore the partition by simply repeating the process(of partition-creation) , Terminal(used "diskutil" command to find the huge 70Gbs file, and to try to resize the single partition/volume to the initial factory-made 250 Gbs HDD)
Tomorrow i will try to learn something about "aliases"(don´t laugh) , because i´ve read something about it that could have an influence on this story.
And now, i´ve reached a point where i can´t read anymore about it...and i can´t go further in "The Search for the Holy Windows-Partition"...so i ask for HELP!!!!
Thank you very much, sorry for the (possible) bad english...

PS: For the readers of this post...i´ve tried then to recreate another windows partition(with success) and i could SAFELY remove it with disk utility. I feel i´ve just picked the wrong tool to do the job...

Thanks ;D

Try this:
1. back up your macintosh HD onto an external HD using timeline
2. reboot your mac holding down the option key and select your external hard drive as your boot disk (it will also work if you use your leopard installation disk as your boot disk).
3. MAKE SURE YOUR MAC HD IS BACKED UP then use disk utility to completely reformat/erase your hard drive.
4. Restore everything back to your mac hd.

Hope you get this worked out!

Cheers.