Dedicated power supply vs tapping power from the pc?

[sdrob04]

I am running 5v for an ipac+optipac and 12v for two coin door lights from my pc's power supply via a xoxide power strip http://www.xoxide.com/pci-power-bracket.html .  I'm pretty sure my power supply is fried (factory 200w in an hp pavilion), as the pc spontaneously shut down about an hour into play and now won't power up at all.  I guess there was no auto-protection mode.  I would never have predicted that two lamps and the encoders would have caused a current drain sufficient to kill the power supply, but it happened nonetheless. 

I would rather not have a second power supply sitting in the cabinet, so I'm wondering if something like a 400w would allow me to run the peripherals without incident.  I do plan to ultimately add some LED's to the control panel, so I need to allow for this as well.  Whatever experiences/recommendations users have out there with respect to power supplies and power supply failures would be greatly appreciated. 

[AtomSmasher]

power supplies are the most common piece of hardware to fail in a computer, it could be your old power supply would have died even if you didn't connect the extra peripherals.  You should be fine with one 400watt power supply.

[BobA]

Power supply is a bit on the small side for extras.  A 400W would probably be fine.  Have you unplugged the existing supply and let it sit for a few minutes?   Sometimes the protection will not reset unless the power cord is pulled and plugged back in.

[miles2912]

I have a similiar config and I used a 350w power supply.  After a few days of running everything I smelt the familiar smell of ozone.

A 450 cured all my problems.

D-