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Installed a new CPU, and PC won't start up, will just switch on fans then turn off and on again repeatedly?

Hi,

For the last 3 years, I've been using an Intel Pentium CPU G860 @ 3.00GHz, and I recently decided to upgrade. My motherboard is a GA-B75M-D3H, and I checked which CPUs it was compatible with before purchasing. Upon realising that the Mobo was LGA 1155 socket, It was clear that my only option was to purchase off of eBay, since LGA 1155 socket CPUs are no longer produced and sold. In the end I settled for an i7-2600k LGA 1155 cpu.

After installing the new processor, I start up the PC and nothing appears on the screen, no BIOS, no nothing. I have illuminating fans in my PC, and they turn on and work, as do all other fans including the heat sync on the CPU. After about 5-10 seconds, it will turn off again, then back on, and off again. It will just repeat over and over with no startup or anything.

To check, I put back in my old CPU, and everything worked just perfectly. Tried putting in the i7 again, and nothing.

Concluding that this is a hardware problem is my last resort, so I've taken to the internet in search of help. The first thing that I've found might help, is resetting the BIOS or giving it an update. Usually, I would dive straight in trying to fix it, but I am hesitant, and have these questions:

What can I lose if I update/reset BIOS?
Is updating my BIOS here the correct decision?
What other approaches could I take to this problem?

I heavily appreciate any answers or suggestions, and thank you very much.
8 answers Last reply Best Answer
More about installed cpu start switch fans turn repeatedly
  1. Best answer
    A CPU swap pretty much always requires a CMOS reset, in my experience anyway. A CMOS reset, you will lose any previously modified bios settings, but that is it.
  2. logainofhades said:
    A CPU swap pretty much always requires a CMOS reset, in my experience anyway. A CMOS reset, you will lose any previously modified bios settings, but that is it.


    Thanks for the swift reply,

    I've never overclocked or fiddled with the BIOS settings so that doesn't bother me. Can I do a CMOS reset simply by unplugging the powersupply/battery and then plugging it back in again? If so, does that open any risks to losing my PC settings?

    Thanks again
  3. You need to unplug the system, first thing. Then there is a jumper that you can use to reset it. Your motherboard manual will state where this jumper is, and the setting to do it. Removing the battery after the system is unplugged, is another option. You will not lose any settings, within your windows install. Only bios settings are reset. If you were using the default settings to begin with, this shouldn't be an issue.
  4. logainofhades said:
    You need to unplug the system, first thing. Then there is a jumper that you can use to reset it. Your motherboard manual will state where this jumper is, and the setting to do it. Removing the battery after the system is unplugged, is another option. You will not lose any settings, within your windows install. Only bios settings are reset. If you were using the default settings to begin with, this shouldn't be an issue.


    At what stage do I perform the CMOS update? Which CPU should I have in the PC when I peform the CMOS? If you could give me a basic step-by-step guide, I'd be very appreciative.

    Thanks
  5. You should reset the CMOS and try the NEW CPU.Many motherboards contain a jumper that can be used to clear CMOS settings if your BIOS is not accessible.

    However, the basic process is fairly similar on all computers. Flip the computer’s power switch to off to ensure it’s not receiving any power. Open the computer’s case and locate the jumper named something like CLEAR CMOS, CLEAR, CLR CMOS, PASSWORD, or CLR PWD – it will often be near the CMOS battery mentioned below. Ensure you’re grounded so you don’t damage your motherboard with static electricity before touching it. Set the jumper to the “clear” position, power on your computer, turn it off again, set the jumper to the original position – and you’re done.
  6. It doesn't matter when you do it. You can leave the jumper on reset, while changing the CPU, then change it back, once the new CPU is installed, if that makes it easier for you.
  7. logainofhades said:
    It doesn't matter when you do it. You can leave the jumper on reset, while changing the CPU, then change it back, once the new CPU is installed, if that makes it easier for you.


    Thank you ever so much. After completing a CMOS reset, it booted up and my new processor is working! Can't thank you enough!
  8. Prior to the reset it may be in your interest to enter the BIOS and make note of your HDD setup. The options are typically IDE, SATA or SATA/AHCI. I suspect your setting is SATA or SATA/AHCI.

    On occasion when you reset the 'default' is IDE ---- that can confuse the system into thinking there is no hard drive since you are using 'SATA'

    You should also verify that the current version of your BIOS supports the new CPU. If you have an older BIOS version it may not recognize the chip.

    edit: Nevermind ... :lol:

    Congrats!
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