TechSpot

you're my last resource!!! computer rebooting at random times...

By dynomaster
Dec 11, 2005
Topic Status:
Not open for further replies.
  1. i need a god of computer maintenance. :angel:
    my friend computer keeps rebooting at random. :dead:
    even on the post screen during boot it reboot. :dead:
    we have changed the following items:

    motherboard (now using a P4P800E-Deluxe)
    memory (now using a PC3200-512Mb)
    processor (PIV 3.0Ghz)
    power supply unit (now using a 450W)

    everything is new, only the problem is the same it keeps rebooting. :hotbounce .
    we cleaned all the others conectors, boards, slots.

    there's no heating issue, the cpu keep 40-50c and
    mobo 30-40c.

    maybe a HD problem, or a cd/dvd recorder but they're almost new
    (6 months)

    if someone can help me.
    i'm still working on it, trying to find a solution. :knock:
    any help will be welcome... :wave:
  2. patio

    patio TS Maniac Posts: 700

    Dis-connect everything except the CPU, video card, one stik of RAM, and the keyboard and mouse.
    Re-boot with a floppy boot disk and let us know what transpires...
  3. dynomaster

    dynomaster TS Rookie Topic Starter

    we have done this. we removed all items inside the case.
    cleaned every boards, connections, contacts. :grinthumb
    the computer worked fine for 1 week, and started rebooting
    yesterday. :hotbounce
    it rebooted random 10 times in 1 hour turned on.
    the computer was just idling, not gaming or even surfing on
    the net... :p

    and the next step is??? ;)
  4. dynomaster

    dynomaster TS Rookie Topic Starter

    we have done everything we know.
    cleaned all the case, mobo, and expansion cards. :knock:

    the only items that remains from the older computer is the HD and CD/DVD drive.
    there's no hardware or software conflict.
    we changed all the hardware because this problem happened with the older stuff too.

    no virus, spywares or other detected.
    just rebooting with no known reason. :hotouch:
  5. JimShady23

    JimShady23 TS Maniac Posts: 651

    Heat sink/fan

    Somtimes a failing heat sink fan or chipset fans is the culprit....Your bios has protection when said fans fall below a said rpm.....
  6. Tedster

    Tedster Techspot old timer..... Posts: 10,074   +13

    ensure you have adequate power

    also your memory may be bad.
  7. patio

    patio TS Maniac Posts: 700

    3 possibilities remain as Tedster and Jim have stated:
    1) Bad memory
    DLoad and run memtest. Do 1 stick at a time and let it run a few hours...any errors are 1 too many if you get them replace the RAM.

    2) Heat.
    DLoad and run motherboard monitor and check your CPU temps...check them 10 minutes after start and after about an hour. Check your MBoard website for what the normal temp ranges are...

    3) PSU
    The PSU is failing and needs to be replaced. Don't buy a cheap one and get at least a 400W
  8. dynomaster

    dynomaster TS Rookie Topic Starter

    a question:
    there's a minimal rpm to run a case fan?
    one of the fans runs 1200-1550 rpms, there's a problem if the speed falls from 1500 rpm?

    no there's no heating problems.
    it keeps cpu on 40-50c and mobo at 30-40c almost all the time.

    and the psu is a new 450W psu.

    the problem started with the old mobo.
    the new mobo (and new items) worked fine for 1 week.

    and now rebooting again, with no reason.

    if exist some type of problem with the following items, please tell me.
    case fans (low rpm? almost 1400-1500rpm)
    hard disk (no problems detected running tests)
    cd-dvd (reading/writing normally)

    the IDE cables are new too.
  9. howard_hopkinso

    howard_hopkinso TS Rookie Posts: 25,948   +19

    Hello and welcome to Techspot.

    Go HERE and follow the instructions.

    If that doesn`t help. Zip 5 or 6 minidumps together, and attach them here.

    Regards Howard :wave: :wave:
  10. Tedster

    Tedster Techspot old timer..... Posts: 10,074   +13

    most new BIOS have a smart fan function. The fan won't come on until the CPU reaches a certain temp. You can overide it in BIOS.
  11. dynomaster

    dynomaster TS Rookie Topic Starter

    but if the mobo have the smart fan function, the fan will move at full speed when the cpu start to heat, right?

    for example, if the fan speed is 1200 rpm, there's a minimal fan speed controled by bios?
     
  12. Tedster

    Tedster Techspot old timer..... Posts: 10,074   +13

    NOT NECESSARILY. It will operate at a speed that's enough to cool the fan properly.
    could be less than max.
  13. patio

    patio TS Maniac Posts: 700

    You are still ignoring the possibility that one or more RAM chips are bad. Follow Howard's suggestions first and then test that RAM
  14. Sharam

    Sharam TS Rookie Posts: 538

    You guys are good with offering help with minimal information!!! I can't, kind of feel slow, but that's only me.

    I still like to know if after changing hardware the operating system was re installed or not and what OS?

    Can you read from the power supply's label and give us the values for +3.3V, +5V and the +12V?

    What kind of video card do you have?
    How many optical drives?
    Is this a new build? If not, when and how did the problems begin?

    450W for a power supply means nothing; I can buy a mid tower with 450W power supply for less than $30.00 Canadian. But my 350W power supply cost me $100.00 alone.

    Still do the minidumps things but your system doesn’t even load your OS most times you say.
  15. dynomaster

    dynomaster TS Rookie Topic Starter

    there's no problem with the memory, already tested. i'll test again and post results later.

    the os is Windows XP, and yes, it was reinstalled after the change of mobo and other components.

    mobo is P4P800E-DELUXE.
    memory is a Sansumg PC3200-512MB.
    the video board is Ge-force 6600, 256Mb, AGP-8X.
    2 HDs, 1 Seagate 160Gb and 1 Hitachi Deskstar 80Gb.
    both hds tested with chkdsk of windows and Norton Utilities.
    i'll try some other utilities to test the hds again.

    and 2 cd/dvd drives.
    both LG, 1 dvd-rom and 1 DVD multi drive.

    and psu voltage data is:
    +3.3v=30A +5VSB=2A
    +5v=45A -5V=0.5A
    +12v=30A -12v=1A

    any more info needed? :confused:
  16. dynomaster

    dynomaster TS Rookie Topic Starter

    this error is not new, it happened with the older mobo, before changing everything too.
    when we assembled the new one, works fine for a week, and started rebooting again.
    there's no dump data, or blue screen errors.
    the computer just reboot itself.
    if the fault was overheating, the mobo will shutdown? right?
    (or i am wrong and the mobo will only restart?).

    the more strange thing is that the computer restart even on the post screen. :dead: don't even reach the OS booting.
  17. Sharam

    Sharam TS Rookie Posts: 538

    Can you try another video card (AGP or PCI) and see if anything changes?

    Let us know,
  18. Fallingleaf

    Fallingleaf TS Rookie

    I don't pretend to know much about this sort of thing so this is a long shot... My friend started to have unexplained reboots on his PC. It turned out that the problem was a failing switch on the system case - once the switch failed it was like someone was holding down the restart switch all the time and as soon as it started powering up the PC would shut down.

    Try disconnecting your system case buttons and switches.
  19. patio

    patio TS Maniac Posts: 700

    Going on this premise sit down and list ALL the components that are still there after changing the MBoard...one of them has to be the culprit.
  20. dynomaster

    dynomaster TS Rookie Topic Starter

    lets explain from beginning:

    the computer was restarting with no known reason.
    the old configuration was:
    ------------------------------------
    mobo Gigabyte (dont remember model)
    RAM boards (PC3200-256Mb X 2)
    Ge-force 5700 128Mb AGP
    Pentium IV 2.4GHz
    PSU with 350W
    1 DVD-ROM
    1 DVD-Multi
    1 HD Seagate 160Gb
    -------------------------------------
    and the new is:
    mobo ASUS P4P800E-DELUXE
    RAM Board (PC3200 sansumg 512MX1)
    Ge-force 6600 256Mb AGP
    Pentium IV 3.0GHz
    PSU with 450W
    -------------------------------------
    the only items that was used on the new configuration are only the dvd drives, hd and case.

    there's not problem with overheating, all temperature is normal.
    cpu temperature is 35-50c
    mobo temp is 30-45c

    already tested memory, hds, mobo status program.
    maybe the problems are the drives?
  21. patio

    patio TS Maniac Posts: 700

    Or it could be shorting out in that case. Check if all the standoffs are in place
  22. dynomaster

    dynomaster TS Rookie Topic Starter

    find the solution... i think.

    disconnected the reset button, dont have restarted even once in three days. when checking the reset button connector with a multimeter, i checked it has contact (like someone pressing it) at random times, even with intervals of a few seconds...

    the reset button seens to be "over"used and the residues inside was the problem. dont connected to test. but everything seens ok now...

    i'll post again in a week, if everything is fine...
    thank you all

    or i can ask for help again...
    but thanks to all that helped me until now...
    and thanks to all "masters" posting on this site to help people like me...
  23. topsites

    topsites TS Rookie

    That was my first guess when I saw the title: Power Supply. In this case it appears the PC PS is adequate at 450w, but how about the house's AC current?
    Are you hooked up to a UPS (Uninterruptable Power Supply)?
    4 years ago I got tired of the power surges/dips in the electricity... Half the time you don't notice it, but the computer sure does.
    For 80 dollars I bought a UPS that keeps me running 5-8 minutes with NO power, even the Internet stays plugged during this time, I have enough time to Save-save-close-close-shut down.
    I haven't experienced improper shut-downs in years, and it has also saved me tons of money in stuff that hasn't fried no more (cards and chips, etc).

    I would seriously consider investing in a decent UPS module, they're guaranteed and it's real nice your computer is on CONSTANT power, no more fluctuations.

    Ok, so you found the problem... I'd still get the UPS :)
  24. Tedster

    Tedster Techspot old timer..... Posts: 10,074   +13

    Oh, I agree. I had an old gateway that bit the dust during a lightening strike even with a surge protector. Now I have my new computer plugged into an UPS that is plugged into an UPS. I haven't had a problem yet.
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