Good evening folks, sorry if I'm interupting the superbowl!

I've just ventured into the world of Laptop hardware repair, and I'm not a fan

Basically I have an Acer 5520 which refuses to POST, never mind Boot.

Essentially what happens is the power button is pressed, it and the HDD and Battery lights light up, some clicking noise from the dvd drive, a slight whir, then silence, lights go off. Then lights back on, clicking but no whir.

I've taken off the back panels and noted what happens. The fan for cpu heatsink is what makes the whir sound, which then stops after 2 or 3 seconds.

I have stripped out and replaced all Ram, dvd drive, hd and heatsink fan (with known working components), re-seated the athlon x2 cpu, and all to no avail!

As a desparate measure I have also replaced the x2, but again no success.

What or where else can I look at to try and resolve this problem?

Any help very much appreciated

Phil