my grandparents recently purchased a pc without my help and advice, from what i can only assume is a very small dealer. There is now a problem with the PC which I am trying to diagnose. After ringing the dealer, it seems his idea is that there is a loose "card." My grandparents seem to think he said the network adapter card, though aren't sure.
After taking a look at the PC it uses a (probably very) basic motherboard, with no onboard graphics, and 2 USB. The upgrade cards installed are USB, Network, and Graphics. The graphic card I will assume is very poor as the maximum resolution is 1024x786.

The problem occurs on start-up, a complete failure to power up.

I cant see how a loose ethernet card can be the cause, and am asking for some more input on this.

opening up the PC at this moment is not an option, as it must remain powered up. (grandparents dont want to risk it not coming back on)
thanks

There's not really much you can do without opening the case, failure to power up is not a software problem so there's nothing you can do, take it back to the place where they got it and

A) Get a refund if you don't feel comfortable with the quality and service.

B) Ask for it to be repaired.

He then can't try and blame you for any of it.

My guess is either one of your hardware devices (CPU, Motherboard) are defective. Either this, or it is a faulty PSU, in which case it would be a terrible idea to leave this PC running. If it's connected to a faulty PSU and left on, there is a very good chance that the entire PC could fry irreparably.

thanks for the help, the guy is meant to be coming to repair it, but if he cant (and i'm not confident that he knows what he's really doing) I'll tell them to get a refund.

thanks again