Thankfully I solved the problem. I tried using the Dangerous Brothers Dos utility to flash the firmware from 1.04 to 3.04 but could not seem to get the syntax right no matter what combinations I tried. The closest I could come was a message telling me to specify the Firmware file to upload. The syntax I used was: â€˜nec3520A â€“sec â€“sla â€“flash 3520ORIG.BINâ€™. This was telling the computer to update the firmware on the NEC3520a which was a secondary slave and to use the BIN file 3520ORIG.BIN but it would not work no matter what spacing I used. I wish the people that made these utilities realised that we are not all experts at Dos. I consider myself reasonably computer literate but I could not do it.
When that failed I then decided to switch the drive to another computer and try to flash from Windows again. I decided to try this because at the NEC site where I got the 3.04 Firmware it said it would not work from Windows if you had Intel Application Accelerator installed. I did not think it was installed but I do remember installing it a long time ago and then realising it was not suitable for my computer and uninstalling it. I did however have other Intel stuff installed for the onboard ethernet and wandered if the Intel software interfered with the flashing.
I put the drive in another older computer which had Windows XP installed but no ethernet or Intel software and when I attempted to flash from Windows instead of the error message and light on the drive continuously flashing to my joy it updated the Firmware to the official NEC 3.04.
I won't be flashing firmwares again for a while until the memory of this ghastly experience is dim. I didn't even backup the old Firmware as I was confident that updating the firmware was a simple procedure which I had already done a few times on other drives without a hitch. Now I know it is not so simple and not to be taken lightly.
Thanks for the suggestions guys.