Computer having trouble starting up.

[cragar]

When I turn on my other computer it shuts off in like 2 seconds. I changed the power supply with another tower that works, and still does the same thing. Does anyone know what might be wrong with my other computer? Any help will be much appreciated.

 

[chiro]

Hey cragar.

Because of the broad nature of the problem it's going to be hard to give specifics without more information but the things I would check for include over-heating, bad connections and possibility of things being wired wrong, CPU-fan not working, and jumper settings if those are an issue to start off with.

Anything that might contribute to over-heating other than the above is also a good place to start.

 

[cragar]

ok thanks for your post. should I take the cpu fan off and put power to it directly to it, to see if it works.

 

[chiro]

Well it's not just if it has any power: also check if its clogged or the air-flow is blocked and whether the CPU has good contact with the cooling equipment (CPU's need a special gel that is applied).

Also check the airflow of the fans that are not on the CPU: make sure they work and are not clogged and do their job.

Do not by any means start your computer without a cooling unit attached to the CPU with the CPU plugged in. These things get hot and if your motherboard doesn't shut it down as a safety measure, then your CPU will cook itself and you will need to get a replacement.

If you want to test the fans, first unplug the motherboard and other devices from the power supply and only plug in the device you want to test (like the fan).

The other thing also that I recommend is to make sure all the cables are plugged in properly and not backwards or some other wrong configuration.

But remember, do not by any means plug in the CPU without a fan: I just wouldn't risk it because if it cooks, its useless.

 

[wuliheron]

If stays on log enough to emit beeping sounds that's a troubleshooting clue as to the problem. If not you could try disconnecting everything except the fans and boot drive and check to make sure there are no obvious shorts or loose connections or funky looking capacitors on the mobo.

 

[Routaran]

i'd try some of the real basic stuff before diving into the deeper things that the other posters have outlined.
First try what wuliheron said, see if you can hear any beeps. Those are error codes, the computer telling you what has gone bad. If you hear any look it up on the internet and it will tell you. You would google something like "post beep code 3 short 1 long" for example.

Try to reboot after each step to see if the issue is resolved.

• Unplug the IDE/SATA cables connecting your CD drive and hard drive from the motherboard (aka mobo)
• Remove the 4/8 pin CPU power connector (should be right next to your CPU) and reseat it.
• Remove the 20/24 pin mobo power connector (should be on the side away from the back panel) and reseat it.
• Reseat your RAM, if you have 2+ sticks, remove them and then just plug one in in DIMM0
• If you have a video card remove and reseat that as well (if you have onboard video, then see if you can remove the video card completely and use onboard video instead)

if after all of that your computer is still not booting, then most likely, the problem is one of two things: (You already tested the PSU so we don't need to worry about that)
Something is wrong with CPU (over heating or failed outright)
Something is wrong with mobo (failed)
if your CPU is overheating, then your mobo may simply be shutting down the system to avoid damage. reseat your heat sink to test but make sure you first get some thermal paste from the local computer store, you will have to wipe clean the contact surface of both the cpu and the heat sink and then reapply a small amount on the heat sink and spread it about.

if that still doesn't work, then we have either a failed CPU or a failed motherboard
your motherboard has several little capacitors on it, if one (or more) of them has burst (capacitor plague) you can either try to solder on the appropriate replacement cap or buy a new mobo. This used to be very common on older computers but is rather rare these days assuming you don't have frequent power surges.

if you cannot see any bad caps on your motherboard the only way to isolate the issue is to put your CPU into another computer(make sure its compatible with the CPU) that is working and checking to see if it boots.
if it boots then your problem is the motherboard, buy a new mobo
if it does not boot then your problem is the CPU, buy a new CPU

 

[winipad]

check your power cables.

 

[r4z0r84]

Try a different location, you may have Dirty Power (fluctuating) meaning the PC tries to draw power but there is insufficient power to draw causing the instant shutdown. or any of the above.