My computer won't start

i was playing with the bios and i changed the memory voltage to 1.90
and from 660mhz to 800mhz

and then my problem began the computer restarted and it wont work the fan works but no beeping
i can see the motherboard lght on
but it just shut off in a few seconds
but then it worked it self and the computer is on now so i thought i should change the bios back to how they were and when i did it stoped working again but this time it would't work again

so i tried to reset the csmo battery nothing changed
can u guyz help ?
5 answers Last reply
More about computer start
  1. Did you clear CMOS correctly? pull plug from wall, remove battery from mobo, press case power switch several times (to help drain psu), go have a cup of coffee, come back and replace battery, put plug back in wall.

    Boot up and go immediately into BIOS. Load Defaults and save. Let it boot into windows.

    If nothing was damaged, that should work. If it doesn't work,let us know what happened.
  2. well i didnt wait for a while i just waited for a min or less
    does that matter ?
  3. Yes, it can. Pressing the power switch several times and waiting several minutes at least is important to allow capacitors to discharge, and let CMOS go blank.
  4. i will try that and tell ya guyz
  5. Work through our standard checklist and troubleshooting thread:
    I mean work through, not just read over it. We spent a lot of time on this. It should find most of the problems.

    If not, continue.

    I have tested the following beeps patterns on Gigabyte, eVGA, and ECS motherboards. Other BIOS' may be different.

    Breadboard - that will help isolate any kind of case problem you might have.

    Breadboard with just motherboard, CPU & HSF, case speaker, and PSU. You do have a case speaker installed, right? If not, you really, really need one. If your case or motherboard didn't come with a system speaker, you can buy one here:

    You can turn on the PC by momentarily shorting the two pins that the case power switch goes to. You should hear a series of long, single beeps indicating memory problems. Silence indicates a problem with (in most likely order) the PSU, motherboard, or CPU.

    Remember, at this time, you do not have a graphics card installed so the load on your PSU will be reduced.

    If no beeps:
    At this point, you can sort of check the PSU. Try to borrow a known good PSU of around 550 - 600 watts. That will power just about any system with a single GPU. If you cannot do that, use a DMM to measure the voltages. Measure between the colored wires and either chassis ground or the black wires. Yellow wires should be 12 volts. Red wires: +5 volts, orange wires: +3.3 volts, blue wire : -12 volts, violet wire: 5 volts always on. Tolerances are +/- 5% except for the -12 volts which is +/- 10%.

    The gray wire is really important. It should go from 0 to +5 volts when you turn the PSU on with the case switch. CPU needs this signal to boot.

    You can turn on the PSU by completely disconnecting the PSU and using a paperclip or jumper wire to short the green wire to one of the neighboring black wires.

    This checks the PSU under no load conditions, so it is not completely reliable. But if it can not pass this, it is dead. Then repeat the checks with the PSU plugged into the computer to put a load on the PSU.

    If the system beeps:
    If it looks like the PSU is good, install a memory stick. Boot. Beep pattern should change to one long and several short beeps indicating a missing graphics card. Silence or long single beeps indicate a problem with the memory.

    Insert the video card and connect any necessary PCIe power connectors. Boot. At this point, the system should POST successfully (a single short beep). Notice that you do not need keyboard, mouse, monitor, or drives to successfully POST.

    Now start connecting the rest of the devices starting with the monitor, then keyboard and mouse, then the rest of the devices, testing after each step. It's possible that you can pass the POST with a defective video card. The POST routines can only check the video interface. It cannot check the internal parts of the video card.
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