Help nexus s issue help please!

[tlasher91]

Hi I recently purchased a nexus s i9023 off of amazon. When I received the phone I turned it on the google logo appears then takes me straight to the bootloader. When clicking on recovery a clockworkmod recovery mode v3.0.2.4 appears. I'm not tech savvy at all and don't know what the issue is. I paid 300 dollars for the phone and can't be refunded so I'm left having to try and fix the phone. If anyone could help me it would be very much appreciated!