Hi.

I think the power supply on my XPS8900 is kaput. Green LED: off. It lights up if I push the test button, but it goes out when I take finger off the button. PC won't boot. What power supply do I buy? The box has a GT 960 video card, and the existing power supply is the stock 460w unit. I imagine I want to replace with a 600w unit? But I am not sure what specs to order against. The service manual and the dell support page is unhelpful.  Installation looks straight forward, except that I don't have a new power supply in my hand to install.  

Any help appreciated.

Thanks