Computer would not boot anymore

[videohalp]

Hello,

I booted my computer and it failed to start the HDD. That happens sometimes because the molex on the HDD is slightly loose. So I readjusted the molex.

Now my computer would not boot anymore!

I hear this faint buzzing sound from my motherboard. Which is common if there was a hardware change. But unlike before, this buzzing sound does not go away after 2-10 minutes. It keeps buzzing for hours.

I have unplugged the power and reseated everything. Still buzzing. I have cleared CMOS. Still buzzing.

I think the buzzing sound is coming from the motherboard speaker. Or somewhere on the bottom-right corner of the motherboard.

There is no sign of hardware damage such as popped/leaking capacitors, rust, or burn marks.

Please help.

[minidv2dvd]

have you got another power supply you could try? i might help if you filled in the computer specs in your profile here also.

[Skith]

I would second having a look at the PSU. Also make sure the PC Speaker lead properly connected to the motherboard. Also, make sure it is not a fan, maybe one one on a chipset or the front intake. Some puffs from a can of compressed air may help, at worst you will have to replace the fan if it is the cause.

Other thoughts:
Do you have power difficulties in your building/area? Brownouts, surges, spikes, dimming/flickering lights, or other such power fluctuations? If so, you may want to invest in a battery Back-UPS unit (one with boost & trim such as the APC Back-UPS RS line). I don't think that will solve your current problem though.

[videohalp]

I tried the PSU in another computer, it is fine.

I am pretty sure the speaker is well connected since it is onboard.

Not a fan. I have disconnected all the fans and still hear the buzzing.

There are power fluctuations in my area. But this did not occur during one.

Got a UPS.

[JimmyS]

If you have multimeter, here is quick test you can do on the P.S. while you have the connector off of the motherboard, to ensure it's making proper voltages (if you don't have a ps tester). Take a short piece of wire that is stripped at both ends. Bend it in a U shape. Put one end in the connector at the green wire spot (PS_ON). Put the other end in one of connectors spots with a black wire (Ground). Turn on the PS. Put one MM probe into another spot in the connector w. a black wire and the other probe at an orange wire spot. You should see about +3.3 volts if you see -3.3 volts reverse the probes. Keep the probe in the black wire spot and move the other probe to a red wire spot. You should see about +5 volts. Then, Yellow = +12 volts, Blue = -12 volts, White = -5 volts. At least you'll know if the PS is in reasonable health. Not fool proof but puts you in the ballpark.

[Video Head]

Check the BIOS to see what errors it will halt on at POST. Try setting it to not halt on any error. If the system boots then you have to look for the problem - bad fan, voltage, etc.

[Nelson37]

Unplug ALL drives, data and power cables. Unplug data cables from the mobo.

Remove ALL cards.

Test.

If you are certain the PS is good, and it still does not work, then remove the board from the case and place on a non-conductive surface and test again.

Would also recommend testing a different PS. It is possible to have an undetectable short in a power cable which is only present when the cables are bent in a certain way.

Do the fans spin, lights flash, any signs of life from the board at all other than the buzzing?

[videohalp]

Tried unplugging/reseating everything already.

Regarding using another PSU, I do not have a spare. But leave the PSU alone, please. The PSU is good. Have been tested in another computer and it works 100% fine. Have mentioned this already in the reply. Therefore, it is not the PSU.

Tested it on a cardboard box surface and still the same.

The fans spins a little when I unplug and replug the power cord.

[Nelson37]

Did you unplug all and LEAVE IT that way? Not Reseat, but Remove.

Your symptom is of a dead short or bad PSU. Remove all possible parts, including KB and mouse.

Mobo, PSU, RAM, CPU. Nothing else connected in any way. No cables, switches, anything.

If still same symptom, then either mobo, PSU, RAM, or CPU is bad, Swap or single-stick the RAM, then you got PSU, CPU, or motherboard. Then you can swap a $40.00 part or $100 + part.

My guess would be power supply or motherboard.

[gll99]

Your description is a bit confusing. In the first post you say it buzzes for hours, then you reset the hdd molex (power?) and now it seems that even the fans won't spin (spin a little when plugging unplugging). Which fans? cpu, ps, extra case fan? I know you don't suspect the ps but that last symptom is a classic ps issue not necessarily the unit but a power connector might not be connected or could be reversed (ie... floppy power connector is upside down), stuck fan causing a power drain etc..

Could you please restate the exact setup you now have and your current observations in greater details. Seems like the problem or symptoms have changed. How far does the computer post, if at all? How long before it shuts off now? You may have accidentally introduced a new problem when you were testing so it would be easier to go through it step by step from the current situation.

I've fixed 3 problems just since the late winter for friends and family and all 3 were ps related although one also blew the video card. I'm checking one now for a friend who says he didn't touch it but I could tell one screw was crooked and the case was not tightly closed. It's an older IBM small form box and it has the same symptom, cpu fan spins a bit on power on and then it shuts down. I'll have to check everything in case he messed something else up which might cause the current problem and could be masking another issue.

btw) As was requested by minidv2dvd it would help if you stated or updated your computer profile.

[darkknight145]

Does it get into the bios at all? if not...
Have you tried starting the PC without the hard drive connected (which is what you were fiddling with) you should be able to get bios screen etc it'll just give an error about the hard drive and stop.
If this happens recheck what you did with the molex connector (also make sure it's plugged in correct way around.
You might have killed your hard drive if you can get into bios without harddrive connected but not with the drive connected

[Video Head]

I agree with the previous posters that the description of the problem is confusing. Does the system not do anything at all or does it get to POST and fail?

You said that you had a loose Molex connector going to a hard drive. Then you say that you "readjusted" it. What does "readjusted the Molex" mean? Did you remove the wires and reinsert them? If so, did you reinsert them into the proper sockets? That could explain the hum. Have you dissconnected the suspect Molex connector to see if the hum stops?

Bad PS or fan, a Mobo shorting on the case or a bad connector or wire on the PS. Although you protest, if it was my system I would try a different PS in the failed system.

[hech54]

Now my computer would not boot anymore!

WILL not boot.

[lacywest]

You really need to say what PC it is ... custom built ... then what mother board is it.

By posting specific info ... me and others can do a search and might find others folks that had the same problem and what they did to fix the problem.

[Video Head]

Now my computer would not boot anymore!

WILL not boot.

What you consider a "boot" is, what videohalp considers a "boot" is, what I consider a "boot" is and what the Marine Corps considers a "boot" is could all be totally different things.

I consider a "boot" to be a sucessful POST, hard drive start and a sucessful OS start. Others might say that a succesful POST is a "boot". That is what we would like to know from videohalp so that we may help them.

[lordsmurf]

It sounds like a bad PSU to me -- I had a problem with something similar this past month. New PSU, no more issues.

[Video Head]

It sounds like a bad PSU to me -- I had a problem with something similar this past month. New PSU, no more issues.

Hey Smurf. As I said, it sounds like a PSU problem to me too.

The OP said to leave the PSU out of it though, because it's not the problem...I wish I had that kind of problem solving ability!

[lordsmurf]

It sounds like a bad PSU to me -- I had a problem with something similar this past month. New PSU, no more issues.

Hey Smurf. As I said, it sounds like a PSU problem to me too.
The OP said to leave the PSU out of it though, because it's not the problem...I wish I had that kind of problem solving ability!

Yeah, I know -- but his method is flawed.
Trying the PSU in another system doesn't mean crap.