P.C. not starting up

[Lampstyle]

Occasionally my H-P Desktop type AT492AV doesn't start at all. It doesn't power up, nothing happens.

When it first happened, i read that you should push all the internal plugs in case one was not contacting.

After doing this a couple of times, the unit starts and runs normally.

I would like to clean the contacts of the most likely plug to be causing the issue, but don't want to disturb them all. Any ideas as to which plug it may be? I don't think the start button is the problem, as it is hidden and I haven't touched it.

[BeemerBiker]

 I have the same 6000 Pro SFF and I have seen that problem occassionally.

Use an air duster to get rid of as much dust as possible then reseat the memory.

Unplug computer.
Discharge static electricity by touching a finger to metal frame or case before removing memory sticks.
Clean the memory contacts with eraser, use air duster in the socket then reseat memory. Reseat one at a time if necessary to find the bad one (if any bad)

I upgraded my system to Q9650 CPU,  SSD, a USB3 adapter, and Windows 10.  I tried a low-profile RX-560 at one time but I pulled it out as it had a large power draw and I was only using the system as an rsync backup for a synology server.

[Lampstyle]

Thanks for the reply, but this is not a systems problem. The computer fails to start up. When you start up normally the fan starts and you get a reaction from the start button, and a light.  in this case there is no reaction at all.

The memory would only come in to play if the computer was alive and working.

I have removed as much dust as possible, and i will ground the chassis to see if it makes a difference.

I really wanted to know which plugs are the ones sending power to start the computer. 

[Lampstyle]

Where can I find a wiring diagram for my P.C., so I can identify the various plugs.

Type AT492AV