PC will not POST or Boot without clearing CMOS (daily)

By Tamste ยท 15 replies
Jul 12, 2005
  1. PC will not POST or Boot consistently

    Hi guys.....first post so please be gentle.

    Had my PC running for over 6 months with no probs, but with an oem XP installation from my desktop. I have since found out that I shouldn't have done this and so went out to buy a copy of XP home for the desktop.

    Reformatted both hard drives

    Installed windows OK, then went to bed

    Next day PC would not boot.

    Fans started

    Floppy drive gave very short clump sound

    Hard Drives and CD Drives woud not spin up

    No nothing on monitor (green light went to amber and stayed there)

    No beeps

    Thinking that this could be a device problem, I opened the case, removed all PCI devices, reseated memory, reseated AGP card, removed heatsink to check contact area and for damage to chip (then reassembled), checked PSU voltages at PSH and on HDD's...........all seemed OK, but no boot.

    Removed CMOS battery for a day, reinserted.......no boot

    Cleared CMOS (jumpered) for 1 hour, reset CMOS then hey presto all came back to life........great I thought until I turned it on the following day only to find that I had to clear the CMOS again before it starts.done this 3 times now and wondering what is wrong.........any ideas greatly appreciated.

    Basic System

    MSI KTS Ultra2 MOBO

    AMD Athlon (Palomino) XP2000+

    640Mb PC2100 DDR RAM

    Q-Tec 400W PSU

    Radeon 9200SE AGP

    2x 80Gb HDD

    DVD Reader

    DVD R/RW
  2. just_a_nobody

    just_a_nobody TS Rookie Posts: 182

    I think your CMOS battery may be too far gone, to hold the BIOS info, so replace that, and see what happens. We have to rule that out, as the culprit, before going any further.
  3. Tamste

    Tamste TS Rookie Topic Starter

    Thought of that, but if that was the case, why did the CMOS not clear when the CMOS battery was removed (for most of the day!). I would have expected to get to bios setup on resteart if the battery was taken out for this period, but I am unly able to get to setup if the CMOS is cleared via the jumpers.

    Will try a new battery though just in case
  4. yea deffinitly the battery

    (did i just say a bad word..only the death and tax......)

    actually i was helping a budy who forgot his password
    pulled battary and (this is really not advised AT ALL)turned on system
    normally till the bios error comes up then I turn off

    any ways lo and behold
    the system booted without the battary
    I left in utter fear
  5. Tamste

    Tamste TS Rookie Topic Starter

    Thanks for the help.

    Will let you know the outcome after I replace the battery

    Once again, THANK YOU
  6. Tamste

    Tamste TS Rookie Topic Starter

    I have replaced the battery and still have the same problem

    PC will boot up normally, but every now and then (about every 2/3 days) all I get is the fans spinning. The PC boots OK if the hard drives start.....maybe this is the problem???

    The only way to boot when it has an off day is to clear the CMOS then try again. Usually on first start post CMOS clearing it says CPU fan not running (when it is). I have reflashed the bios just in case it was corrupted, but still same problem on restart.

    I have removed everything from the MOBO and rebuilt from scratch.
    I have tried starting the system with no video, with no memory, with no drives..........same outcome every time.

    Now I am running out of ideas. Any views on what it could be, or what to try next would be greatly appreciated.

    When it does boot, everything seems to be running fine.
  7. Tamste

    Tamste TS Rookie Topic Starter

    OK....more recent info.

    I left the PC switched off but plugged into the mains for a couple of days, and for some reason it started first time enery time I tried it.

    I then tried turning off at the mains and 6 hours later came to use the PC. On this occasion I pushed the start button to get (sequential tries a couple of mins apart)
    1. Fans running, no start
    2. Fans running, no start
    3. No response fromn start button (tried several times)
    4. eventually a normal start without to reset the CMOS.

    Any idea how to check if this is a PSU problem (though voltages to drive when just fans running appear normal), or is it likely to be a MOBO problem (capacitor??).
  8. Tamste

    Tamste TS Rookie Topic Starter

    Problem appears solved and was linked to the variable speed CPU fan fitted.
    The fan was set to automatic control (via a sensor taped to the heat sink). When I took the fan off automatic and placed it in manual control, normal functionality returned.

    my next suggestion was are u running a 3 pin or 2 pin plug for fan

    o well! cool

    thanks for posting your authored solution

  10. Tamste

    Tamste TS Rookie Topic Starter

    Sorry to raise this again, but following a trouble free month of daily use with no hardware changes (not even looked inside the case), the bl**dy thing has packed up again.

    Current state is there are no fans or power when the power button is pressed. Having rehecked for bad connections and even fitting the old heat sink fan, no joy.

    If the "system on" is frigged on the power connector, everything comes back to life except the video.
    Fans run
    CD/DVD drives run
    Hard disks run (and keep running)
    No POST bleeps
    Monitor light turns from green (pre power on) to amber and does not change back to green.

    I have tried frigging where the power switch connects to the mobo, but no joy......not even a whisper of life. Only works once the power on is frigged on the connetor block.

    Any ideas as to what this may be gratefully received
  11. PanicX

    PanicX TechSpot Ambassador Posts: 669

    not positive myself, but sounds like your case power switch maybe bunk. However to me it also sounds like your scraping by on a failing PSU.
  12. Tamste

    Tamste TS Rookie Topic Starter

    Could be PSU, but this is relatively new and when the PC runs (up to yesterday) all voltages were as expected (in BIOS and MSI's utility). This is the first time I have had a no POST when the fans haven't started. There is power to a couple of pins on the connector (both 5V).

    Wondered about the power switch so tried shorting the power switch contacts on the mobo but no response. Is there a way to test the power switch, or another wy to bypass it?
  13. I,m sure you already know you can ohm out the switch and push the button
    I guess the best way would be to run a couple of volts above the normal usage with a led or something that would come on in series with the switch

    i dout thats it though

    when i took my class for a+ cert my teacher swore up and down that if mobo
    doesn't post then mobo is bad (being there's and error beep for all else)
    he was wrong

    4 days ago i accidentally pushed to hard on my monitor while getting out of my game chair(skateboard size desk with momo wheel , 2 1" square bars to either side of wheel bolted to desk and extending about 4" past back of desk where my flatscreen is mounted with vertical bars on both ends ,this all mounts on a steering colum with a gas shock to help with tilt sterring)
    I apperantly snapped one of the cold flourescent somthing or other and it sent a 6000 volt spike to my gfx5700ve
    needlesss to say they were both fried (blew a hole through the heatsink on video card)

    sorry for babbbbelinggggggg

    the point is i got no post at all until i tryed a new video card

    i hope this helped

    l8r steyr223
  14. Tamste

    Tamste TS Rookie Topic Starter

    OK, here's an update on the problem.

    I have tried frigging the start button and swappig the switch with the restart button. Neither managed to start the PC.

    I then jumpered the start on the power connector again with it connected to the mobo to force a start. After several starts where it managed to flash the LED on the optical mouse, light up both DVD drives and start the hard drives it still failed to get the video going.

    Eventually it did start and I was able to remove the jumper on the power connector (onto mobo) and all seemed to work as normal.
    Tried several soft boots (restart) and all went well.
    Tried several hard boots and again a normal post and start.

    Switched all power off overnight and it would NOT start in the morning unless the connector was jumpered again (but failed to start video). Walked away in disgust and tried the power button (not jumpered on the PSU/MOBO connecter) 10 mins later and got a normal start.

    I am less convinced that this is a power button problem, and my attention is switching to the PSU. It seems that if the PSU is cold (no 240V connected for a while) then I risk having a problem. If the power is left connected to the PC when it is switched off, I seem to get a normal start.

    Can anyone please explain why this should be so, or advise me differently if I am missing the poiint?
  15. Tamste

    Tamste TS Rookie Topic Starter

    Well, problem sorted.

    Changed the mobo for a new one, and no further problems with cold starting.
    Posts with no problems, even with the CPU fan on auto control via the temp. sensor on the heatsink.

    Thanks for all the help.
  16. tekal

    tekal TS Rookie

    Hi guys

    i have the same problem but my problem came when i had cleared the cmos, when i turn the avr on the motherboard automatically power up without pressing the power button.

    hope u guyz can help me i am so disgusted with this problem. thanks in advance..
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