PC wont boot, tried everything I can think of!!

have you tried without the video card

are you sure theres no chance a standoff got left off where the mb could be grounding to case....maybe try mb out of case...without anything else plugged in except what is needed to boot

They probably test it and saw that it was working and sent it back.

That is what they do with 90ish% of motherboard returns since most of the time people return motherboards there is nothing wrong with it.

Returning to the issue at hand:

Surge protectors aren't foolproof.

Power problems come in many different forms.

One of those is a power loss. Another is a power surge. There are other types as well.

Surge protectors often work by converting a power surge into a power loss. When they detect abnormally large amounts of current they may just trip a switch and cut the power to everything connected in order to keep the excess current from flowing to the devices.

Both power loss and power surge are things you generally want to avoid.

The way to attempt avoiding a power loss is with something called an UPS. It lets your computer stay on for about 15 more minutes after the power goes out so you have time to shut it off correctly.

That being said, some UPS devices can have power surges flow through them (no surge protector components) which means if you had a setup of wall -> ups -> surge protector -> computer you could still experience a power loss if a surge was converted to a loss by the surge protector.

Still, in the overall scheme of things the wall -> ups -> surge protector -> computer is about the best protection you can have for your computer (don't switch the order of the middle components).

Whatever your problem ends up being, I would suggest you consider getting this sort of setup so the same problems are less likely to occur in the future.

I have exactly that setup and power outages have never destroyed my components. My house, however, hasn't been struck by lightning, so a surge could potentially screw me.

In any event, it is usually the case in these sort of situations that either 1) the PSU is dead, or 2) the PSU and something else it was connected to are both dead.

I need to know more about your PSU situation in order to help identify the cause of this behavior.

What are the manufacturer, model, wattage, age, and if possible the part number of both the PSUs? Avoid just glossing over this question. The better you answer it the better you can be helped.

A lot of people underestimate the importance of this item even though they would not underestimate the importance of the engine in their car. Avoid being one of those people.

Also, I need to know if you have any potential to try these two PSUs in some other computer, ideally one that is worse than the current computer you are trying to fix. If not then a newer computer that isn't great will still be better than nothing.

yes I did try with the video card out.
I have not yet tried it with the entire mb out of the case though.

Thank you for the info, very detailed.

K, so, the Power Supply Unit is:
Diablotek UL Series
675 watt
ATX 12V 2.31 ver compatible
140MM Silent Cooling Fan
Full Sleeve Cabling

Model # PSUL675
Brand New


It has:
20+4P Mainboard Connector x1
8P CPU+12V Connector x1
4+4P CPU+12V Connector x1
6+2P PCI-E Connector x2
Sata x6
Molex x6
FDD x1

This Power Supply Unit is brand new right out the box.
But if you feel it will definitely help to still try it in another machine, I can and will.
Also, This is the second brand new PSU, exact same model and specs, that I have tried right out the box.

Thank you for the PSU info.

I would still like you to tell me the case info and I would still like you to try both of them in a different computer.

I can tell you at this moment that the brand Diablotek doesn't get a lot of respect around here, because from our point of view they are not truthful in their advertising.

The temperature of PSU components makes a very big difference in the operation of the PSU. A PSU that can put out 100w at 0c might only put out 50w at 20c.

The PSU brands that people here like (primarily Seasonic) rate their PSUs at the temperature that they are likely to be used at in the real world. If it is likely it will be 70c inside the PSU during normal operations, then that is what temperature they test at when they are determining the wattage on the labels, or perhaps an even higher temperature.

Diablotek, however, doesn't do this (along with most brands that aren't Seasonic). They either 1) test the maximum wattage when the device is in Antarctica OR they just straight up lie on the label. You can take your pick. This means the wattage is probably 2x or more of what the value would actually be in regular operations.

A handy rule of thumb to tell if your PSU is rated at regular temperatures or at super low temperatures is to divide the total wattage by the price. If you paid $1 per 10w, then it is likely to be rated at regular temperatures. If you paid $1 per 20w, it is likely the device was rated at sub-zero temperatures.

What this means to you is that the more expensive one works when the less expensive one fails. You get what you pay for.

All other things being equal, the higher priced PSU wins.

After rebates, an XFX 450w costs right about $45 on Newegg right now shipped. Some Diablotek models you can get 500w for $30 or even less.

Admittedly, the one you have is actually kinda pricey if it is the one that I think it is.

Personally, I know this brand is not truthful all the time, so I have reservations about accepting that it is truthful in the marketing of the UL 675w version as well.

The UL series claims to have low noise and ripple on the packaging, but they make a lot of rosy claims on the 500w for $25 boxes too.

I would rather see you try an XFX (Seasonic) 650w in the PSU, but I will work with what I have at the moment.

Trying the 2 PSUs in a different PC would help to determine a little about their capabilities in regular conditions at least.

I looked for a review of the Diablotek UL lineup from a website that does real performance testing and could not find any. Usually that is a very bad sign and it means the company would prefer their PSUs weren't tested by anyone with real testing equipment.

When PSU makers do this and they are otherwise known to have a bad reputation, I can only assume it is because they have things to hide in this model line too.

If you have any capacity at all to exchange the new one for anything at all from these brands, I would do so: Antec, Corsair, Seasonic, or XFX.

Otherwise, please let me know the other information I asked for and whether these PSUs work in other PCs, preferably better computers than yours if you can find any.

The case is Antec 900
The other/old PSU I originally had was Antec 650w

The PSUs do work in my brother's computer, which is not better than mine, but closely equivalent.

Ok so tell me if I have this right:

Old computer running just fine with Antec 650w.

Power goes out, possibly damaging PSU.

You get a Diablotek 675 UL and stick it in there. Things look exactly like they did when the Antec 650w was still in.

You take the Diablotek 675 UL back to the store and trade it in for another one of the same exact kind.

You take that home and put it in the case. Things look exactly like they did with the Antec 650w still in.

You try this 2nd Diablotek 675w UL on the brother's PC, everything works beautifully.

Am I up to speed on everything pretty well?

Tell me, what PSU does the brother have and are you able to try it in your PC?

Better yet, if you are able to borrow stuff from his computer while you are trying to narrow down the root cause of the problem, what are his full system specs including maker/model of everything?

Yes you are up to speed very well.
I believe he has a 450w power supply, not sure of the brand and model.
I will be home later tonight and will be able check all the specs on his machine as I am not sure off top.

Let me know with a new post when you get the new info please, and if his PSU works in your computer too.