Before I take my desktop for repair...
 

The story from my wife is that my son powered down our Dell studio desktop (using the power button)and it simply won't power up.

Any troubleshooting techniques I can use before I take it to a shop?

with PC, one symptom can be caused by a ton of issues.

Straight up no power after working fine? Likely the power supply


switch it out with a known working one, if it comes on and works correctly, order you a cheap power supply and call it good. You can get a power supply that will last several years in the 25ish dollar range. If you want a nice one, plan on spending 60-80. In your case, some pre-built dell? Go with the cheapy :P

Be a ton cheaper than taking it in.

If you where local I would do it for you :(

don't take it to best buy
if it's PS you're looking at more than $150 probably, maybe even $200

Need more info.

Won't power up as in no lights no sounds no electricity?

green light in back near a/c cord

Do you hear any beeps when you hit the power button or just nothing at all?

Nothing happening on screen? No sounds?

no sound, no fan, no beeps, just a green light near power cord in back

turn off the power source switch, unplug it for 10 seconds, plug it back in, turn on power source switch again, then turn it on at the regular computer power button

Save yourself the trouble and switch the power supply with a known working one. Takes 5 minutes. If it boots, there ya go.

By his description of the situation, there's no chance in hell he has a spare power supply sitting around...

I guess that's possible.. but I figure there is one in the computer he is posting from~

I guess it could be his phone. :)

Most likely either a dead power supply or dead motherboard.

Is the green light physically on the same piece of metal that you plug the power cord into? There should be a square section where the power cord plugs in. If the light in physically on that part, then that could indicate that the power supply is working and has voltage, but the motherboard is fried. Or it could be the light from the motherboard, in which it's still hard to tell whether it would be the power supply or the motherboard.

I remember once my laptop wouldn't power up. Click the power button and, literally, nothing happened.

Turns out I had to do some really weird shit like hold the power button down for 30 seconds then remove and reinsert the battery. I could be remembering that wrong as it was a long time ago, but I remember for sure that I had to hold the power button down for an extended time.

It worked just fine after that though. Very, very strange.

I'll upload a pic in a bit.

I'm working from a lap top at the moment