i've got a msi video card that cycles a few times until you wiggle the connectors then it boots. the old quadro card didn't have this problem. the board has 75W slots with a 8600GT (46w card) so its not a power problem. its plain odd
i put a 7300GS OC in which should draw similar power and doesn't happen. so i figure the msi card is not up to snuff quality standard.
try reducing the power draw (unplug some fans but not cpu duh) or extra components and see if its the power supply tripping.
my workstation has 460watt 80 plus (energystar 4.0) power supply that can be factory equipped with two decent quadro cards (real ones) that eat a ton of power. I've seen that config in action works fine so i know its not the problem.
only does it on cold boot too, never crashes. orthos tested (i just pin modded the cpu from 1.8 to 2.4 too). rock solid nvidia test.
probably crappy design on MSI since the HP oem vid cards and the BFG 7300 GS never exhibit this problem.
heck i can plug both the 7300GS OC and the MSI 8600GT in and the system boots fine only when i wiggle the msi card doesn't matter which pcie port i put it in (both are 75watt).
I'd rma the card but it doesn't bother me that much. only paid $64 for the msi 8600 GT OC
you might check the hard drives i've had a bad one (bad as in this type of problem) do this odd problem took the drive off and put in another (bigger,faster) and problem gone. you'd hear the drive spin up then click down as the system sorta cycled. odd. rma'd it got the same drive model back and never saw a problem since.