Asus P5WD2 Premium - No 24 pin power or no EZ_PLUG found.

Hiya.

I'm getting a message every time I boot my machine and I'm not sure why. I'm by no means an expert on hardware stuff so I wondered if someone might be able to help?

It's an Asus P5WD2 Premium motherboard. Recently, since adding a hard disk controller, whenever I boot I get a message saying:

"No 24 pin power or no EZ_PLUG found. Press F1 to resume."

I press F1 and everything seems to be fine, although very occasionally (maybe one in every 10 boots) I just get a black screen and XP doesn't load. I press the power button to reboot and then it's fine on the next go. I don't know if this is related to the message or not.

On the motherboard there's a socket labelled EZ_PLUG. I have connected this, but the message is still there. I've also made sure that the 24 pin power is connected.

Does anyway have any idea on what this might be?

Thanks loads for any help!

Wolo.