WD Netcenter power light flashing amber and cannot access data

WD External Drives External Drives for PC
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When I try to turn up my WD500B019 NAS disc amber led turn into flashing amber and blu but not become blu and I cannot access the disc. I connect the disc (it’s a SATA) to my computer but I don’t know the filesystem. WHat data recovery sooftware I should use? Even if I manage to recover my data, how should I format it? Could I change it with another disc?