shut mine down one night and the next morning no go, picked up a power supply and fired right up, good thing is for a standard non flashy power supply for HP they should start at like $25 depending on the model, rip it out and bring it with so you grab the right one. I go here
http://www.microcenter.com/at_the_stores/index.html but not sure where your at but any good store should have a nice selection.