Searching Google, I found this. Do you have a new video card?
quote:
I figured out what the problem is...
...
I guess the new video card was drawing a little too much power, and was causing the splitter to not get enough to properly power both drives, although they were being detected. So I found my original converter I had when I only had one SATA drive (a single 4-pin molex to a single SATA power) and hooked that to one of the drives, and then hooked the dual one to the other (just leaving the other connection loose), and now all works beautifully. So it was a power issue, but created by an odd setup.
Luckily, one of the PSU's in my 2nd computer went recently, so I decided to upgrade my main PSU to a 470W Enermax and throw this PSU in the 2nd (a 350W quality Antec which will be powering a much less power demanding issue)
http://www.dslreports.com/forum/remark,13952093?hilite=dmi
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