I just bought an unlocked Blackberry 7290 online, and I can't figure out how to get the operating system on it. I keep getting a message stating 'no system software installed. Presently, I do not have any service set-up. Do I need to do this before I can set-up the OS. I am an absolute noobie with Blackberry, so any help is greatly appreciated.

Thanks.

Have you installed the desktop manager and downloaded the OS for your device ?
That should be your first steps, also you can check the FAQ's on this forum
Regards

install the desktop manager and then install the OS ,connect your 7290 to pc.click the desktop manager icon.choose the apps you want.After your phone reset,it's ok!