Hi mate,
No overclocking - I just put it together this week, its an E8500 running at stock. Initially I thought it was the boot sequence but the BIOS said no, then I thought the power supply wasnt up to it but I realised the USB HDDs have their own power supply!
Seeing as it boots up and is stable when the USB HDDs are not attached, and is stable if I power them on after boot up I've concluded that it doesnt like USB HDDs! This means the board isnt suitable for me unless their is a fix/workaround as I'm concerned about switching on the HDDs manually in case it has any longer term effects on their reliability. I have 5 USB HDDs - I'll try booting up with just one attached and see if its a particular HD...