PC won't start this morning...

Put the PC to sleep last night normally. Pushed the power button this morning and got a brief (less than a second) attempt at starting, then nothing. Cycled main power to the box and tried again. Nope. What is interesting is that it keeps trying to start - once I've pushed the power button, it will keep cycling with brief flashes of the power button light and the drive activity light every few seconds, but never get beyond that. I can also hear the fans come on with the light flashes. There's no video output at all (monitor confirmed working). It keeps trying until I stop it.

Given the very short attempts I'm guessing the power supply is dead, but I'm happy to hear other suggestions. I'm deep in preparations for the fall semester and I really don't relish trying to complete them on my Chromebook.

Air, spark, fuel, compression...

It's worth taking the cover off just to make sure the PS connectors on the mobo are on tight.

unplug the power cord from it for a few minutes then try it again

Power supply or hard drive.

Also, check if all the fans turn on when you try to power it on. Some systems won't start if for example the CPU fan has failed.

Power supply is my first thought.  Are you willing to share any specifics regarding the system?  Age? 

I'm not home until this afternoon, so I can't try anything or give exact specs, but it's a box I built a few years ago. Intel i5 on an MSI motherboard. Power supply, IIRC, is a 500w Corsair. It's not full of dust or anything, no crazy overclocking, lots of venting and fans - temps never get even close to high.

OK, just got home. I had already pulled the tower out of it's corner and had it open to check the internal connections - all good. I grabbed a spare power cord and tried to start it up with nothing plugged into it and it spun up - all fans seem to be running. Shut it down again, moved it back to its spot, plugged in the peripherals, and we're back to the same problem. That seems to me to be further indication of the PS being the culprit. Unless someone else has an alternative theory in the next little bit, I'll be of to Best Buy to see if they still carry any actual computer components.

I've got a house full of computers.  I've probably put a power supply in every one at least once.  They are pretty much the only component I've ever had fail in a system, but 3 to 4 years is all I can ever get out of a power supply.  The low end junkers that are sometimes included with a case are the worst.  I had one shoot sparks out the back after about 12 months.  That was fun.

Edit:  Come to think of it, I should probably order a new 650-watt supply just to keep around as a spare, for when the inevitable happens....

This one isn't a bargain basement special, but it is probably 5 years old at this point. As you say, even if it turns out not to be the cause of my current problem it's not bad to have a spare around. Off to Best Buy....

And we're back in business. BB had exactly one PS to choose from, so I ended up with a 700w Thermaltake. We'll see how long it lasts.

Of course, because nothing can be simple, my 128i threw an ABS light on the way over there, so now I get to figure that out. Yay, 2020....

I've had pretty good experience with SeaSonic PSUs. They do seem to last well, but they're not exactly the cheapest PSU around.

02Pilot said:

And we're back in business. BB had exactly one PS to choose from, so I ended up with a 700w Thermaltake. We'll see how long it lasts.

Of course, because nothing can be simple, my 128i threw an ABS light on the way over there, so now I get to figure that out. Yay, 2020....

Probably just a failed wheel speed sensor.

In reply to z31maniac :

That's what the magic box says - right front this time. I just replaced both rears for the second time in less than a year. One failed in less than two months. Thankfully I got them from FCP, so the replacements will be credited. I haven't touched the fronts on this car yet, so I just ordered two and hopefully that's end of it. Assuming they last more than two months.

Well, crap. After replacing the power supply everything was fine until about an hour ago. I was working on my laptop elsewhere, but walked back to check something on the desktop and found it unresponsive. Pushed the power button and I'm getting the same behavior as before - attempted starts that repeat about every five seconds, but it never goes anywhere. I'm going to pull it out and look for anything I might not have gotten tight when I replaced the PS, but I checked it pretty closely when I did it. Any other suggestions as to what might be going on here?

EDIT: Unplugged it from the UPS and stuck it straight into a wall outlet. Got it to start in safe mode, then restarted normally. The odd thing is that it is not detecting my monitor correctly, and is stuck in 1024x768 VGA. It sees that the video card is present, but it doesn't seem to be outputting correctly. Some sort of default mode for a failing video card? It's original to the box, so it's probably time to replace it, but I don't want to just keep throwing parts at this thing if I don't have to.

Not many options locally. Best Buy has an EVGA 1650 Super or a PNY 1660 Super in the price range I'm willing to spend. Any opinions on these? I've had EVGA for a long time and liked them, but the PNY seems like a good jump in performance, and for $40 I might be willing to defect.

See if someone on FB Marketplace or CL has a video card you can nab for cheap?

I'm not on FB, and I'm pretty skeptical of used electronics, especially when I'm trying to nail down a problem.

Have you tried reinstalling the drivers for the Vid card?  If you just want something cheap to test with I have a bunch of cards, I can send one.

In reply to Aaron_King :

I appreciate the offer, but my impatience and need to get this thing working got the better of me, and I already ran to Best Buy and grabbed the EVGA 1650 Super. It's in the box now. Unfortunately, when I started it up I had the same problem - monitor stuck in 1024x768 VGA. I dug into it a little and found it was not detecting the PnP monitor. I haven't touched any of the settings or monitor cable, so I started playing with the monitor's own menus to see what I could find. It was on auto input detect, so I switched that to manual - no joy. But I then switched the HDMI cable to the other port on the monitor, and lo and behold everything came back to normal. It appears that the port on the monitor may be the cause here, which is damn strange. I've never seen a monitor fail like this (usually they just go black), but hey, if it solves the problem, I won't ask any more questions.

You might try unplugging it, pulling the side off, pulling the CMOS battery (thin disk battery on the MB), pulling the RAM and cleaning the contacts with an eraser, pulling the video card and doing the same, then reassembling.  You will have to set the date and time when you boot the system.

It would also be a good idea to blow out the power supply (blow through all the vents in the PS case until no more dust comes out) as well as blow out heat sink on the processor. 

Dust creates heat and heat is the enemy of electronics.

In reply to CJ (He's Just an FS) :

Did think about the CMOS battery - it was on the list had I not gotten results messing with the video card and monitor.

I'm very careful about dust and heat. The room the box is in is fairly dust-prone, but I take it out several times a year and blow the dust out with compressed air (yes, I immobilize the fans so I don't backfeed any voltage through the system). I also monitor temps and it runs quite cool even under load - it's a box case with tons of vents and multiple fans.