You could probably power it with a splitter cable, IF the PSU is quality. I am not sure how many rails that PSU has or how good HP is with their PSUs. I would grab this if you don't plan to CF. http://www.newegg.com/Product/Product.aspx?Item=N82E168... $40 with rebate and promo code. GREAT DEAL!!!!
Edit: Found the name of the power supply (Bordeaux-C).
I thank you very much for providing an alternative power supply unit, but I am a little hesitant to drop that kind of money for potentially only 40W of power and having to redo all the wiring.
Does anyone happen to know anything about the quality of Bordeaux-C psu's?
I don't know of that PSU maker, which means it is mostly likely junk. Trust me, the PC Power and Cooling will give you much more than that. It is VERY high quality and supports 500w only on the 12v rails. With all of the rails, it supports 600w. I would do it.