No video/sound/mouse/keyboard output

[drigan]

Hi, i have a computer that died a slow death on my sister. For about a month it would randomly shut down on her, and would not restart for a long interval afterwards. (A number of hours.) Naturally, she couldn't give me any specifics about what she was doing any time the computer shut down. :( Eventually, it stopped turning on altogether.

When i took the cover off and tried turning the computer on, the CPU fan would spin a few rotations then stop. There were no other signs of life.

I swapped out the PSU and the Mobo. After swapping the mobo, everything *seemed* to work (The fans spin and lights blink) . . . but the monitor still shows nothing. I swapped out the video card, and still nothing. I tried a different monitor, still nothing. I've even tried swapping the ram . . . i'd have tried swapping the CPU if i had an extra laying around, but i don't.

Here is where the status of various parts of the PC:
CPU Fan: working
Mouse: light works and dims when left alone for a while
Keyboard: does not have any working LEDs, when caps/num/scroll lock is pressed, the LEDs do not respond.
CD drives: LEDs work, but won't open or accept CDs
Hard drive LED: constantly on
power LED: not connected to the mobo (hey, i just got lazy, ok?)

If anyone has any ideas on what could be wrong, i'd really appreciate it! Thank you and Peace,
Joe :)

[RGPHNX]

Hi drigan,
If I'm reading you post correctly re:

When i took the cover off and tried turning the computer on, the CPU fan would spin a few rotations then stop. There were no other signs of life

and...

. i'd have tried swapping the CPU if i had an extra laying around, but i don't.

then..
unfortunately I probably have some bad news :( :(..
the CPU fan not working for an extended period of time "probably" caused the CPU to overheat & burn up.
This is a very common result of CPU fan failure.
Sorry.
But since you have already installed a new mobo .. then ..you should probably have a tech pop in a new CPU to test it..before you rush out to buy a new CPU yourself.
Hope this helps, :)
RGPHNX
ps-if you have other troubleshooting issues.. check out my website for soultions.

[drigan]

Hi drigan,
the CPU fan not working for an extended period of time "probably" caused the CPU to overheat & burn up.
This is a very common result of CPU fan failure.

Thank you for the reply! But, I don't think that's the problem, because the fan worked fine with the new mobo. The fan just happened to be the *only* thing to show *any* signs of life when i turned on the computer with the old mobo: there weren't any LEDs or anything.

Perhaps that's not a good assumption, but i think it is . . . if you disagree, please let me know, and i'll just spring for a new cpu . . . it's about the only major piece i haven't replaced anyway. :sad:

Peace,
Joe :)

[RGPHNX]

Hi again drigan,
The CPU fan not working on the old motherboard is the exact reason that the CPU is probably burnt NOW & from before. When you changed the motherboard the CPU fan came back to life because it gets its power from the new motherboard ( IT WASN'T GETTING POWER FROM THE OLD MOBO).
The burnt CPU is the reason your leds on the drives & keyboard don't blink/cycle because theyre not getting any IRQ (interrupts requests) that tell them to turn off/on etc. ALL These requests have to come thru the CPU.. but your CPU isn't working properly.
Trust me on this one. Either the CPU is burnt OR the connection to the mobo is bad (too much/ or no connecting grease; bad pins ..etc). Anyway have a tech check it out before you buy a new one. They should probably do it for next to nothing anyway (if you buy the new CPU thur their shop).
Good luck :)
RGPHNX

[drigan]

but why would the LED's work on the new mobo? I'm using the same CPU. :/

[RGPHNX]

Hi again drigan,
The LEDs on the mobo (and the hard drive & front panel & CD & floppy etc.) don't get their power from the CPU.. they get it DIRECTLY from the power supply itself. The LEDS are supposed to be constantly on/"lighted up" unless the signals from the CPU tell them to shut off. The CPU has nothing to do with whether the LEDs initially light up or not. The CPU only has controll over when the LEDs shut off/"blink".
RGPHNX

[drigan]

Ah, ic, that makes sense. Thank you! (I just wish i didn't need to get a new CPU now!)

[RGPHNX]

Hi again drigan,
Get the repair technician to check out your CPU BEFORE you run off & buy a new one. I'm 99% sure that is your problem... but .. there's a 1% chance that there's some other problem with the new motherboard. But I can't tell you if this is so without checking it out with a meter. So, have the tech check out both.. it won't cost you any more & it might save you the cost of a new CPU.
Good luck ;)
RGPHNX