I wanted to reboot my imac to factory settings now its stuck on the OS X utility screen

What model iMac is it? If it was manufactured pre-OS X Lion (10.7) there should be two grey disks supplied with the Mac. If you have disk 1 you will need to boot from it and need to erase and re-install the OS from that disk.

The previous owner of the Mac should have passed the Mac on with the OS that was installed on it when new (together with any disks). As you've discovered, it looks like the OS has been updated using the previous owners AppleID.

You may be able to get round this situation by resorting to Internet Recovery (if the Mac had OS X Lion or later on it when new). This should install the OS on the Mac that was on it when new, assuming it was Lion, Mountain Lion or Mavericks. The original OS is tied to the machine itself not an AppleID.

Rebooting holding down Comand + Alt + r should boot you into Internet Recovery. You'll need to have a good connection to the Internet - wired would be better than wifi - as the download is several gb in size.

More info here: http://support.apple.com/kb/HT4718?viewlocale=en_US&locale=en_US

From the Apple Menu (top left of the screen) Select 'About this Mac...>More info' - it should tell you there.

Just reboot and hold command+option+R (per Paul31's instructions)

If your machine is too old to have Internet Recovery, nothing will happen.

Post back.

Kristina260 wrote:

and also where can purchase a refomating disc

You don't need to. However, if the Mac is pre-Lion and you didn't receive any disks with it you will need to phone Apple to order replacement disks that are specific to your machine in order to erase and start with a clean slate.

Tell us exactly what happened when you tried to boot to Internet Recovery, what did you see? was there a rotating globe?

Can we start over? Restart the Mac with it's current OS installed and go to the Apple Menu 'About this Mac' as posted above and tell us what Mac you have.

Do you get this menu when you click the Apple (top left corner of screen)

Yes or no please.

I'll respectuflly disagree with Paul_31's advice about ordering replacement disks. We know that whatever your model is, it's capable of running Mavericks. But there are some models of Macintosh that shipped with OS X 10.5.x that can be upgraded to Mavericks, and if you order exact replacement disks for that model from Apple, you will wind up with the 10.5 operating system, which can't be upgraded to Mavericks by itself, since the computer needs to be at 10.6 to upgrade to Mavericks. You can purchase OS X 10.6 installation disks from Apple for $19.99, but that, too, may be useless, because your model may be too new to support 10.6.

http://store.apple.com/us/product/MC573Z/A/mac-os-x-106-snow-leopard

CSound1 is on the right track, because he's probably trying to get you to a screen that can display information about your Mac - such as the serial number, and perhaps the amount of installed memory.

If you can't get to a screen to show your serial number, see this link:

http://support.apple.com/kb/ht1349

Once you get your serial number, you can get general (and more specific) information about your Mac from one or both of these links. (The second link is not an Apple site, but has reliable information):

https://getsupport.apple.com/ProductSelector.action

http://www.chipmunk.nl/klantenservice/applemodel.html

Once we know more about your model, then we can advise you how to proceed. Here's another question. Is it your intention to completely erase the internal hard drive of the computer (which will also erase all of the installed programs on the computer)?

jimkessler wrote:

I'll respectuflly disagree with Paul_31's advice about ordering replacement disks.

We've been trying to get Kristina260 to tell us exactly what Mac it is. I suggested that replacement disks would be required if the Mac was of pre-Lion vintage (see my third post).

If the Mac is pre-Lion the disks will be required, and it they haven't been provided with the Mac, replacements will need to be ordered from Apple.

I disagree. If the computer originally shipped with OS X 10.6, then the replacement disks from Apple may be appropriate. If the computer originally shipped with OS X 10.5, then the replacement disks from Apple would be a waste of money for the task at hand (which I assume is erasing the computer's hard drive, reinstalling the operating system, and then probably upgrading to Mavericks). The only benefit of having the original 10.5 disks from Apple would be Apple's Hardware Test on the second DVD, and (for sake of argument) reinstalling any bundled applications that Apple happened to include on those two DVDs. But those bundled applications under 10.5 (iLife primarily) would be too old to run with Mavericks, thus necessitating paid updates.