My CDJ 900 Nexus wont turn on. help!!

I was using them(2) last night for a party I had. I closed up shop, turned everything off, the usual. Packed it all up, and it was sitting in my room all day today, untouched. I go to turn them on this evening, and one works fine. and one starts to turn on, then turns off again completely. It wont boot completely. any ideas? I think it might just be the CDJ...