Error Booting ReadyNas 104 - Boot from USB Failed!

I have my NAS set to boot at 4PM everyday and shutdown at 1AM every morning. This afternoon when my NAS booted it dislayed on the LCD screen:

Boot from USB
Failed!

I cannot ping the NAS nor can I access the web admin interface or any of the netwrok shares :smileysad:

After reading through the forum the suggested recovery method is creating a USB Recovery Tool to install the latest OS: How-do-I-use-the-USB-Recovery-Tool-on-my-ReadyNAS-OS-6-storage-system however it states this should only be done when the Netgear Technicial Support has recommended it.  Does anyone have any other suggestions on how I can revive my NAS or shall I take the plunge and try the USB Recovery Tool?

For reference:

• I have a ReadyNas 104
• I have 4 x 3TB WD Red drives installed.
• No USB devices are connected to the NAS.
• I'm not sure what Firware/OS Version my NAS was running however I'm positive the last update I did was back in March which suggest I may have been running v6.9.3 as this version was released around that time.
• I've tried booting the NAS without any hard drives installed and I get the same error displyed on the LCD screen.
• This issue has happened randomly, it was working fine yesterday afternoon.