Repeatly Rebooting on BIOS

I built a new system for myself about two and a half months ago. This morning just after booting up and logging in, my network adapter wouldn't connect to my wireless network (something that has happened before) so I shut the computer down normally and started it back up. After starting it spent a long time (~10 seconds) on the BIOS screen before restarting. It then kept restarting (getting to the BIOS screen or reaching ~1 second in) until I manually cut the power. All further attempts to boot up have resulted in the same loop. I have removed all unnecessary devices (USB adapters, etc), removed my RAM sticks individually, removed my video card, and removed the power cables to my harddrives. Nothing effects the behavior. The computer also will not accept any input from my keyboard (so I can't do anything at the BIOS screen). I suspect/hope that it's my PSU (I had no problems with the system yesterday). Is there any way of testing it before using the warranty? It could also be my CPU or motherboard.

CPU: i5-2500k
Motherboard: Gigabyte GA-Z68XP-UD3 LGA 1155 Z68 ATX
PSU: Corsair Builder Series 600 Watt ATX 12V Power Supply
RAM: 2x G.SKILL Ripjaws X Series 8GB
Video Card: GIGABYTE Ultra Durable VGA Series GV-R685OC-1GD Radeon HD 6850
Case: HAF 912
SSD: Crucial M4 64GB
SSD/HDD: Seagate Momentus XT 500GB
Optical Drive: ASUS 24X DVD Burner
Operating System: Windows 7 Home Premium 64-bit
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More about repeatly rebooting bios
  1. Please write out the maker/model of every component in the whole computer. That means the case and everything inside of it.

    There are resources available to test things, but before we go into that, I would like to know more about the system.

    If you have a second PC or a friend or family member with a PC, you could ask them if you could borrow their PSU as a basic test.
  2. Updated my OP with the component list.

    Unfortunately, I don't believe any of the PSU's I have access to would be compatible.
  3. Could be the PSU, but without a second PSU to try, it's hard to rule out.

    I would remove the data cables from the drives as well (some motherboards can sense something there, and cause funny things).

    Also, have 1 memory module installed, if the same failure happens, swap that module out for the module you removed first.
    If after those tests you're getting the same results, probably worth RMAing the PSU. But still doesn't guarantee that's the fault, unfortunately...
  4. Update: I removed all of my data cables and reset the BIOS back to the factory default. No change unfortunately.

    When the computer boots for more than 2 seconds, I get the system boots successfully beep from motherboard. On one boot, the system didn't actually shut back down on its own like usual and, instead, stayed on the BIOS screen for ~1 minute before I shut it off. This seems to imply that the motherboard may be responsible, correct?

    Edit: I've got an old computer with a 305W power supply. I can't remove it (it's a prebuilt and not designed to be removed) but I could bridge it over if the wattage is enough. I haven't done a wattage calculation for my current computer but I seem to recall that it was less than 400W.
  5. Best answer
    I'd suspect the PSU first. Statistically speaking these are much more likely to fail over a mobo. Plus it's so much easier to RMA/swap a PSU than a mobo. :)

    But, unfortunately without extra equipment for you to swap/test, it's hard to narrow it down completely (other words, the mobo could still be the culprit). But that's what the warranty replacement is for (swapping to new parts).
    Fingers crossed it's just the PSU...
  6. Quote:
    Edit: I've got an old computer with a 305W power supply. I can't remove it (it's a prebuilt and not designed to be removed) but I could bridge it over if the wattage is enough. I haven't done a wattage calculation for my current computer but I seem to recall that it was less than 400W.

    If it's the PSU in the older system is technologically compatible (same connectors, etc), it's worth a try. Just don't connect the HDDs/SSDs. Not letting the system boot an OS, plus doing so without the extra hardware will almost certainly keep you under the 300W threshold.
    But I wouldn't advise letting the system fully boot off of that PSU. None the less, if you can get a complete POST, you have your answer.
  7. Take the video card out and connect the monitor via HDMI. See if that makes a difference.

    Try the RAM sticks individually and disconnect any drives that only have data on them and not Windows files. Disconnect any CD drives that are connected.

    Also, what model of old computer do you have that you can't take the PSU out? You should be able to just plug the cables from the other one into this PC, although it might not be pretty it should work as long as it has the right connectors.

    Without the video card and that other stuff, even the old PSU should be able to breathe life into this PC.

    Anyway, answer/do that stuff and I will see if I can come up with any more for you.
  8. Unfortunately, my old PSU doesn't have all of the right connectors so I can't use it :(.

    I've already disconnected my DVD drive and tested each RAM stick individually, no luck there.

    I've got access to a newer computer that would be compatible but I'll have to ask the owner whether or not I can use it for the test. I could also try some local computer repair shops to see if they have a power supply tester (and if they don't I could always buy one online). Or I could take the adventurous route and use the multimeter I have around here somewhere.
  9. Don't bother with a power supply testers because they can't do load tests which are what exposes the real problems in a PSU. Most of the time, the PSU only fails when it is near its load capacity (not what it says on the box), and they can't really simulate that.

    Also don't bother with the multi-meters. They are made to test linear power supplies, they can't tell you anything about switching-mode power supplies (PSUs).

    See if you can borrow that other computer or at least some parts from it and let me know. It would be really helpful to sort this out.
  10. Best answer selected by Paladin5.
  11. So I ended up bringing my computer to a local computer repair shop and they swapped out my PSU. Their conclusion is that it is fine and that, unfortunately, it is my motherboard that is bad :(. Thanks for all of the advice.
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