Can't I resize my existing partition? I tried installing Win 7 into my Mac so I can dual boot and use Win 7 but then again changed my mind about it but i have already partitioned a separate drive for windows. I deleted it and tried resizing my start up disk but failed in doing so. I'm using Mountain Lion OS and my lap is a MacBook Pro. 

I need to reconnect the Macintosh HD with the free space below. Please help me out. 

Since Im new to this forum, I cant publish images. If you guys could be kind enough to give me your email address i could mail the image to you. Thanks a lot.
When resizing the partions you will need to also boot to an external drive or DVD. Once booted to that you should be able to resize the volume without any problems.

If you don't have an external drive with OSX loaded on it. You can download the Recovery Disk Assistant (http://support.apple.com/kb/DL1433) which has disk utility on it. This will just load onto a flash drive.