Hey there Hobbit Shado,
It sounds like you are trying to update to Mavericks but are unable to becuase of a partitioning problem.
You cannot reformat the drive you have the OS installed on while it is running. I would recommend booting to Safe Mode, or using the disk utility to verify and repair the permissions and/or the disk itself.
Check out this info from the article named:
Resolve startup issues and perform disk maintenance with Disk Utility and fsck
http://support.apple.com/kb/ts1417
If you're using Mac OS X 10.2 or later, you can start up your computer in Safe Mode, which includes an automatic disk check and repair. If you're using Mac OS X 10.1.5 or earlier, skip to the next section. A Safe Boot, which starts up your computer into Safe Mode, may allow you to start up your computer successfully using a reduced version of the system software. To do this, follow these steps:
- Start up in Safe Mode.
- After the system has fully started up, restart your computer again normally.
If the computer successfully restarts, you do not need to do any more troubleshooting. If the issue persists, try Disk Utility.
- Start from the Recovery System or Internet Recovery (OS X Lion or Mountain Lion).
If your computer shipped with a Mac OS X Install disc, insert the installation disc, and restart the computer while holding the C key.
- If using a Recovery partition or Internet Recovery (OS X Lion and later): When your computer finishes starting up, choose Disk Utility from the Utilities window.
If using an installation disc: Choose Disk Utility from the Installer menu.
Important: If you started from an installation disc, do not click Continue in the first screen of the Installer. If you do, you must start from the disc again to access Disk Utility.
- Click the First Aid tab.
- Click the disclosure triangle to the left of the hard drive icon to display the names of your hard disk volumes and partitions.
- Select your OS X volume.
- Click Repair. Disk Utility checks and repairs the disk.
Tip: With Mac OS X v10.6 and earlier, always start up your computer from an Install or Restore disc when using Disk Utility to verify or repair your startup volume. Otherwise, you might see some disk error messages.
Thank you for using Apple Support Communities.
All the best,
Sterling