How are the drives formatted - RAID 0, RAID 1, JBOD, Standard? And you do have a recent tested backup of your data I hope.
If you don't have a backup you could well be in trouble because your drives will not transfer to another NAS without reformatting. RAID 1 is the only array that doesn't require special software to recover data and even that requires care and attention to detail as well as a LINUX computer (you can use a live linux DVD and external USB hard disks).
REMEMBER: Any data that you don't have at least 2 copies of is not backed up.