Mobo shutdown wierdness

I've run up against an odd problem I've never seen before...maybe you all have! I just got an Asus P5A (you know how I love SS7 systems), but at shutdown it just goes to the "it's now OK to shutdown" screen, even though it's ATX...does the same in Win98SE and Win2kPro. Then the real wierdness: it won't power up again unless you pull the plug and let it sit for a while. Tried a second PS, same thing I swear I can hear something go "tink" and then it will boot again. What the heck is this mobo doing to my power supplies???


JC