With a new comp, you gotta stay with it man. PSU's usually last more than 8hrs are fine. So yeah, gotta monitor a new comp build, especially the PSU. I'm sure it might have something like a defective fan that died and then the PSU fired. Happened to me within well, 10mins actually.
Open your comp, see if you can smell burning. Might have fried something. Bad placement of thermal paste can fry chips (and oh how I've learnt this bad problem.. stupid thermal paste on fingers that gets everywhere..)