Does prtdiag show and issues with the power?
Has the server been stable since the initial event?
If so there is a procedure within the documentation to the server where you can manually from the LOM prompt turn the fault LED off. All you need to do is check your documentation.
Stuart is right, what if this problem had happened over night, no-one was ni to notice and then just came in the next day and no lights were on. There would be no indication of a problem unless you are either monitoring the system messages file via some method (which we all do religiously!).
The system is telling you it had a problem, it expects you to investigate it and sort it out. When you are happy, turn it off and it will chug along like normal.
Of course, if it is an intermitent hardware fault then it will come back on again, so we can look further into it then.