Yeah I didn't think it was the hard drive either. All of her data fit on a 32GB flash. I told her I would hold on to the machine if she wanted to try another power supply. Yeah I've never fixed a mother board or monitor either. Late reply a little under the weather.
First thoughts if you are getting power but no picture, it would usually be either the monitor or video card. With these all in ones have probably one power light on monitor. Color differences in power light can tell you some things.
Hard to test certain components on this as it's All-In-One. Also try to troubleshoot this with the manufacturer of PC, thought i linked the sites to you, i am not sure of the warranty status of this PC.
Would not suggest new drive or reinstalling windows, as the problem is no picture possible power or motherboard issue, it won't probably help you.
Under the weather, sorry to hear, i am fed up with weather here lately !!
Possible voltage issue with Power Supply or motherboard, yes replacing this on system like this, i am not even sure of and is it worth it for this type of system, if it is this.
Edited by jds63, 23 February 2015 - 03:35 PM.