It's my first post on this forum so pleasre bare with me.
    Yesterday i tried fitting a new RAM card on my motherboard, and it took me a while to see that it wouldn't fit (though it was a DDR2 and should have). I thought it was in , but it wasn't, and started the PC. Only the cpu fan got some power, spinning for a bit and stopping, same as the hard drive.
    I've changed the RAM back, but the same probblem. I can press power on multiple times in a row to get the cpu fan to "normal" startup speed, but then it stops again. Figured it was the PSU so i've opened it up to find some popped caps. So, i've changed it, but the same thing happens again. 
        When i press power on, cpu fan spins a little, HDD gets some power for a few spins, then nothing. No caps are popped on the motherboard. 
    Any ideeas would be appreciated. Would like to know if the motherboard is toast, or how i could tell if it is.

Swapping out the motherboard would be the easiest way to test the rest of your components. However, not everyone has motherboards laying around. Have you verfiied that your power supply is OK? Checked the outputs with a power meter? If all of the power is OK, then all you need to do to get the motherboard up and running is the CPU and RAM at a minimum. Unplug all other components and see if the fans spin up and you get a video feed.

if ur cpu fan start & then stop completly after after few second, then ur cpu fan creating this problem, u can remove the cpu fan & make shour it is not damage, install after check , tray one s without istalling ram, if same problem showing , problem with your mother board & power supplay. just tray it.

I hope you are using a surge protector... perhaps hmmm. i am still wondering why the RAM wouldn't fit....maybe a shard of metal got into the RAM slot and caused a short? and now the replaced PSU is not giving enough power? try starting the machine with only power to the motherboard (no harddrive, no optical drives, no floppy, etc) check the rating of your new PSU compared to the old..enough power? but really i think a shard of metal is causing it.

Never try anything which you are totally not aware off ! Its ok if you work on small things like changing ram, keyboard, mouse etc but never play with motherboard as its very delicate and can be damanged with a slite push in it.. So why dont you take it a professional and learn it from him !

have you checked the motherboard specifications 'cause there are some some rules for the memory of ram you put in the second slot of the motherboard.

Disassemble motherboard from CPU completely
now remove SMPS
now 1) keep the motherboard and all components on wooden surface like table
check RAM Check CMOS Cell
2) attach all components like ram,processor&SMPS
3) Now power on try it if the problem same persist try this another method
4) see your motherboard's CMOS Cell's Near A JUMPER resetter
once yuo find the jumper i am sure youcan find on motherbord some where printed
like " clear CMOS/Normal CMOS" Now Remove jumper for 30 Sec
5)set upon normal CMOS start again try this

if problem persist again give me your motherboard model No Like DG31,D945,946,G41etc

mail me gajendra.rajput22@gmail.com

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