Monitor, keyboard and mouse do not work

[--= Blade =--]

Hiya,

I have just recently opened up my computer to check that everything is ok and upon booting it up, neither monitor, keyboard or mouse work. I have tried rebooting but no change. The monitor does not receive a signal, the keyboard lights do not light up (even the numlock) and my laser usb mouse does not light up either. I have disconnected and reconnected all the cables on the back of Pc and all cables inside too.

Thinking it could be one of the components, i have changed the graphics card and sticks of Ram but no luck. What could it be

Prior to this, the computer was working fine, just being abit slow that's all.

Please help as i my brother has his final school coursework on the PC which he needs to hand in.

Thanks.

[rolling bear]

first, if you need the work in a hurry disconnect the power, then take out the harddisk and read it with another pc.

now as for your problem. it might be coincidence you started having problems when you opened your case, on the other hand if you were unfortunate, you might have shorted something with electrostatic in your hands. did you touch anything?

it's better to be grounded with an antistatic wrist. I think it unlikely all keyboard mouse and monitor stopped working, so there's something wrong either with booting or some hardware component.

possibly you could clear the CMOS (there's a jumper, disconnect power then move the jumper, read the manual of motherboard). alternatively, disconnect power, take out motherboard battery for 30 seconds (some say 10 minutes), this will clear the CMOS sometimes more effectively.
this might let you boot.

if you're totally sure the graphics card and all ram sticks are fine, that would leave the CPU, or power supply.
it might help if you say what components you have (as good brand power supplies don't fail too often , while cheap ones do much more so).

[rolling bear]

if you clear the CMOS, you have to go in the BIOS and check any settings (like voltage, frequency) are fine because it resets to BIOS defaults. if the default is a higher voltage, it might damage your component in the long run

[nihil]

Hi,

You might try checking the CMOS battery or just replacing it.

How do the keyboard and monitor connect to the PC?

Whilst it might be the PSU, I would suspect the motherboard before the CPU.

Does it try to boot and do you get any BIOS beeps?

[wh666-666]

I would suspect the psu first, then the motherboard.

If you can, a quick check is to grab a psu out of another system of yours and check it out. If it still displays the same symptoms, then the motherboard is the next likely culprit.

[--= Blade =--]

Hi,

I have tried replacing the PSU with a new 400w one but no difference. There is no bios beeps when i boot up the machine.

So far i have replaced the Ram, HDD, PSU, CMOS Battery and AGP Graphics card. I do not have a spare CPU so i'm not able to replace that. After changing all these, still it does not work.

The keyboard is via ps2 port (stadard purple port) and my mouse is usb optical.

I'm thinking that it may be the motherboard. What you guys reckon?

[wh666-666]

Yep, if it isnt the psu it will be the mobo. It would be very rare for it to be the cpu, they can take a lot more abuse than people think.