Pull the drive from the current system and put it in another system that has Windows 7, XP, Vista - whatever. Using Disk Management Console, initialize the disk and define the file system whether NTFS or FAT or whatever you plan on using. Then, when the disk is inserted in the system you are using it in, it will register correctly. This is because the array has to be deleted from the RAID BIOS or Option ROM on a system before the RAID array is dismantled. If you fail to do so, the disk will appear to still be a part of an array and will be inaccessible in Windows. You must first initialize the disk and then define the file system type for the drive to correct this issue. Why, well when two drives are in a RAID array, the logical disk that is created is defined both in the RAID BIOS and the MBR on the logical disk that you created by linking two drives in a RAID array. Even though you can remove the drives physically from the array, they will still have that code that says - hey where's my other drive for my logical disk array? This is why you are having this problem. If you need help with this let me know. Should be an easy fix if you follow the above.