Grey screen after reboot and keychain password problems..

It's hard to believe I have only had my iMac 1 week and already I have managed to lock myself out of my user account and now after following online advice to unlock the keychain within utilities, I have a grey screen and spinning pointer. I remember deleting something from the keychain but now I can't even log on?

Is there anyway I can resolve this myself ( very little technical experience) or will Apple phone support be my best option? Any answers would be greatly appreciated.............. thanks in advance.