I'm no expert, but one thing springs to mind, and that's the fact that your PSU may be suffering and unable to drive such a large system with multiple hard drives. I'm sure you're not running on a stock 300W ATX supply, but you don't say what PSU you are using, or what voltages you are seeing on the voltage lines.Maybe you should try another PSU, something like an Enermax 550W ?:)

Thanks Jock:I have a Enermax PSU as listed in my original post. Not quite 550 Watts if I remember correctly, but it has worked well for a couple of years now. You are right in suspecting this though. The generic PSU that came with my case which was 550 Watts caused computer shutdowns originally when I cranked up FS9 (couple of years ago). I replaced it just for a try with a good 350 watt unit I had on the shelf. Everything worked fine then until some weeks later I received the higher powered Enermax unit. For what it is worth, the generic unit weighed about half what both the old 350 watt and new Enermax weighed. Brand does make a difference with power supplies at least, even more than power capacity.Reinstalled Windows and it cured my drive recognition problem. It did originalte duplicate documents and settings folders though. The Hassle of editing paths for many items was a mess, so I reformatted and started from scratch again.Everything works fine now.Thanks again for the suggestion.RTH