problem with installing W7 on mac !!

I have new macbook laptop, and I installed Windows7 beside mac x operating systems. After that I deleted W7 and tried to install it again and unfortunately i deleted W7 and a part from Disk Utility.

Now the problem is when I try to install windows7 by using Boot camp assistance it gives me a message telling me "The startup up disk can not be partitioned or restored to a single partition, the startup disk must be formatted as a single mac OS extended 'Journaled' volume."

How can I do that, I am a new user to mac.

Regards

You've basically modified the partition map in such a way that Boot Camp can't resize the volume. Next time you feel the need to remove a Boot Camp partition, don't use Disk Utility, Boot Camp Assistant will do it for you cleanly.

Probably the best way to do this would be to backup your OS X partition using a tool like SuperDuper! or Carbon Copy Cloner (CCC) to an external. Boot from the external and then completely format the drive to a single Mac OS X Extended (Journaled) volume. Then, restore the backup to the newly formatted drive, run Boot Camp Assistant to create a Boot Camp partition and install Windows.