Yesterday I cleaned my pc, removed RAM, disk, and cpu fan(not cpu). After the clean-up I re-connected all the components again only to find out that the computer starts but reboots after a few seconds(the power supply and cpu fans turn up and then turn down... and repeat until I disconnect them).

Hardware specifications

  1. Power supply: Corsair CX 750
  2. Board: GA B85M-D3H
  3. CPU: Intel I3 4150
  4. HDD: Seagate 160GB/1TB
  5. RAM: Kingstom 2x 2GB

I didn't miss a connection or touched the cpu. I think that would be the BIOS deprogrammed or corrupt. In this case how could I re-program or update the BIOS if I couldn't event access to it? Can I re-program/update a bios from another computer?

I have searched in several supports forums but anything worked for me.

What do you recommend in this case?

Thanks in advance.


Your motherboard manual, which you can find a link to here, has a layout map on page twelve.

In the lower right hand corner of that map, there's a pair of pins that are labeled "CLR_CMOS". It is labeled by reference number 15. CMOS is the onboard memory storage for your motherboard, and is used to save BIOS settings. The CMOS memory can be cleared in two ways without booting the computer or accessing BIOS.

  1. Follow the instructions on page 18 to short the pins and clear the CMOS memory:

Use this jumper to clear the BIOS configurations and reset the CMOS values to factory defaults. To clear the CMOS values, use a metal object like a screwdriver to touch the two pins for a few seconds.

Always turn off your computer and unplug the power cord from the power outlet before clearing the CMOS values.

After system restart, go to BIOS Setup to load factory defaults (select Load Optimized Defaults) or manually configure the BIOS settings (refer to Chapter 2, "BIOS Setup," for BIOS configurations).

  1. Pull the CMOS battery from the board for a few seconds before replacing it. This is located near the center of your motherboard, and is round like a watch battery. In the diagram on page 12 of your manual, you're looking for number 5 labeled as "BAT".

After you successfully clear the CMOS memory, factory default settings should be restored and you should be able to boot the machine normally. Make sure to enter BIOS and re-configure any necessary settings before booting to your operating system.

If that doesn't work, my next order of business in terms of recommendations would probably be to take your power supply into a local shop for testing. This is usually free but you can always call ahead to make sure.

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