one for all you desktop geeks ....very strange

Discussion in 'Lounge & Gossip' started by jimjams, Wednesday 7th Sep, 2016.

  1. jimjams Guest

    a bit long this, but very strange ...

    My middle son lives in his own house. Yesterday he told me that his PC was not working, and described the symptoms, which were that when he switched it on at the wall, there was a clicking noise from the PC, the fans would start, then it would switch itself off, then there was the clicking noise, the fans would start, then it would switch itself off, etc, etc until he switched it off on the wall.

    I went over to look at it, disconnected the mouse, keyboard, monitor, removed the covers, switched it on at the wall, and sure enough it did what he said. So internally I disconnected the power-cable and sata-cable from the hard drive and from the DVD drive, and tried it again. Same symptoms.

    Next I removed the PSU. The cables were routed in all sorts of annoying places, loads of tie-wraps, and I had to remove the graphics card out of the way while I extricated the PSU, then I put the graphics card back.

    With the PSU outside the chassis, I switched it on without connecting anything to the PC. It clicked, and remained on. I switched it off-and-on, no click. I waited about 5 minutes, switched it on, and it clicked (so there must be a relay inside that latches on when the power rails are stable, and capacitors hold the rails for a while when switched off with no load). Then I connected the 24-pin cable to the motherboard and the 4-pin cable adjacent to the CPU, and switched on. Same symptoms as in the beginning.

    So I brought the PC and PSU home with me. At home I have a PSU tester, and I plugged the 24-pin into the tester and all the LEDs lit up on the tester. Same for the 4-pin and the sata power cable. I then plugged the 24-pin and 4-pin cables back into the motherboard, switched on, same symptoms as in the beginning.

    I switched off, removed the graphics card and all the leads to the front panel, switched on, and the green LED on the motherboard lit up and stayed like that i.e. waiting for the ON button. I shorted the ON-pins with a screwdriver, the PSU clicked, the fans started, and it all kept running. So I switched it off, plugged in the graphics card, plugged in a monitor and keyboard, switched on the PSU, shorted the ON-pins and it powered up and I got it into BIOS.

    Finally, I switched it off, plugged in all the leads to the front panel, switch on, pressed the ON button, and it all powered up and I got it into BIOS. I left it like that for 3 hours, and when I came back it was still sitting in BIOS. I have switched it on and off many times, and it all runs ok.

    I called my son later, and he says that before this all started, strange things were happening. The PC is 2 years old, it was Win-7 but it upgraded itself to Windows 10 some time ago, and in the last week things kept popping up on the screen and disappearing, it started to run very slowly, and the day before the on-off-on-off symptoms started, the mouse would not work sometimes, so he powered it off on the wall. The only anti-virus he has is free version of AVG, and he says he visits a lot of web-sites to get free movies.

    I reckon that there was (still is) definitely a virus/trojan in the operating system, and possibly someone was trying to install a virus into BIOS. But what I don't get is how the BIOS has corrected itself, and if it has, is there a virus in the BIOS now ?
  2. SpeedyGee Administrator Staff Team

    England Speedy Birmingham
    It's been a long long time since I messed with PCs, PC hardware and BIOS stuff but there should be a BIOS reset jumper on the motherboard itself.

    I wouldn't have thought it's a BIOS virus though more likely to be a hardware fault somewhere.
    jimjams likes this.
  3. Zebster Guest

  4. jd1959 Valued Contributor ★ ★ ★ ☆ ☆

    Ireland Zack Kilkenny
    No idea not a computer guru, but I've been having big issues with the windows anniversary update causing all kinds of problems with lagging freezing, stalling etc on the two laptops at home. Finally tracked the problem to a conflict with Avira, or malware bytes, or spybot. Once I uninstalled them cleared the windows download folder and forced the update they seem to be running ok again. Possibly something like this going with yours?
    jimjams likes this.
  5. jimjams Guest

    the basics of fault-finding are
    1. remove components back to a minimum configuration to see if the fault disappears (if it doesn't then it's not repairable at a "system" level)
    2. add components back to see when the fault returns

    what concerned me was that the fault did not return i.e. I expected the fault to return when I put the graphics card back in, or when I re-connected the cables to the front buttons. But that did not happen, which pointed to some kind of BIOS fault.

    But I have now managed to "simulate" the fault.

    When you switch the power on, if you hold the ON button down, the relay in the PSU clicks, the motherboard powers up, then a couple of seconds later it powers off and stays off.

    But if you keep pressing the ON button quickly, the relay in the PSU clicks, the motherboard powers up, then a second later it powers off, the relay in the PSU clicks, the motherboard powers up, etc, etc.

    So the fault must have been in the wires to the ON button, or in the ON button itself, but I am puzzled why it has cleared itself.

    I now think that there were two separate and coincidental faults
    1. fault in the ON button that has gone
    2. fault in the operating system, I will run it in safe mode to find out (not re-connected the hard drive yet)

    btw several years ago I had a laptop running XP that ended up with a root-kit virus so I know what to look for (the only way round a root-kit is to completely re-install the operating system, a BIOS virus is one step further than a root-kit virus, but I now doubt if this is a BIOS virus).

    FWIW the motherboard is ASUS M5A78L-M
  6. Bios reflash might sort it.
    jimjams likes this.
  7. jimjams Guest

    if it turns out to be a BIOS virus then that's the only way round it, but I no longer think it is.
    I've connected and run the hard disk now and it seems ok, I wouldn't know if it's slow though, or if there are any strange processes, and his AVG free looks ok and ran a full scan ok.
    He can have it back in working condition now, only time will tell if there is something wrong other than weird fault in the ON button.
  8. exec Club Veteran ★ ★ ★ ★ ★

    United Kingdom London
    BIOS virus are not easy to do, very much doubt that is the case, its good to add a password to the BIOS to extra 'secure' it. Sounds like it had a hardware fault, I would reformat the PC regardless and install Win 10 from scratch. Also tell your son to use Kodi. :Wink:
    jimjams likes this.
  9. jimjams Guest

    Yes that's true, BIOS is specific to the motherboard, so a BIOS virus has to be code that can fit and run same as an update would. Not only that, there has to be sufficient connection for the update to take place.

    Because the desktop was switching on and off, I suspected that a non-completed attempt had been made, and that somehow the old BIOS had managed to put itself back before the incomplete code was totally bricked.

    But I took the working desktop back to my son and demonstrated how the symptoms were identical if you keep pressing the ON button, both in the way it shut down originally, and in the way it then continually powered on and off. I asked him if he had spilled any liquid onto the top panel and he said no, but then I suggested that maybe one of their cats had urinated onto the top panel and he said that that is a possibility.

    unless ...

    Last edited by a moderator: Friday 9th Sep, 2016
    exec and SayamaAccord like this.