Howdy vince_mcclain81, the posting from Apple above your name "If your Mac starts up to a question mark" should be pretty helpful to you, and as Allan Jones posted, if you have a set of system install/restore DVD's that might have been included with your '09 iMac, you could use those to reinstall the Mac OS, holding down the "C" key on the keyboard on startup and sliding the appropriate dvd into the dvd drive, label side UP. IF you DON'T.....you could try rebooting from the Recovery Partition on your iMac (assuming it has one) by restarting and holding down the Apple (command) and R keys together on the keyboard on startup until you see a language selection screen. Pick one and continue....Disk Utility might be available from that menu, but if not, move your cursor (the arrow) to the top center of your screen and click. You should now see "Mac OS X Tools", from there, Disk Utility and Terminal should be available.... run Disk Utility to make sure your built in hard drive is OK.....then you could re-install the Mac OS.... to change the login/admin password and name, you'd have to go to Terminal, run that.....you'd see a white screen with black letters, which is OK for terminal. type in *resetpassword*, all 1 word, but without the *'s. press enter/return on your keyboard and it'll get you into the main login/startup/admin password reset application....
that's all I have
John B