PC not booting

I'm trying to put together a brand new computer from parts I got from newegg. It's using a Pentium 4 2.26Ghz, 512MB PC3200 DDR ram, Radeon 9600 video card, and an old 10Gb maxtor hard drive. I ran into a problem when I first started putting it together where when you try to turn the PC on, the fan on the CPU starts for about half a second, then stops. Nothing else happens. Then when you turn the PC on again, nothing at all happens. I was told it might be a defective motherboard, so I sent it back to newegg and got a new one. A few minutes ago I finished putting it together, and now the same thing is happening.

It was suggested to me before that I take the motherboard out of the case and only hook up the CPU, ram, video card, and hard drive. I did this, and the same problem still happened.

So now I am back to where I was two weeks ago, and I have no idea what to do now. I don't know if it could be a bad PSU, bad ram, bad CPU, or what. I don't have another computer that I can test the parts in, since my other computer uses 4x AGP and can't take PC3200 ram. Are there any other suggestions as to what I might be able to check or do? Thanks.

 

keep the mobo out of the case laying on a piece of cardboard, what you want to do is try just to get a post. You don't need the hdd for this.

Install the cpu/hsf, 1 stick ram, video card, psu,keyboard and monitor
Make sure all jumpers are set correctly, clear the cmos by unpluging the psu from wall and moving the cmos jumper to pins 2&3 for a few minutes then make sure to move jumper back to pins 1&2.

Make sure the fan connecter from the hs is installed on the correct header on the mobo, make sure the 20 pin connecter from psu to mobo is seated correctly, make sure the 4 pin connecter from psu to mobo is connected.

Now plug in and touch the 2 pins the case switch connects to with a screw driver, this will turn system on, see if it will post.
If not then remove the ram and have a case speaker pluged in or if voice post then speakers. Did you get any beeps?

Post back with results. What mobo and psu are you using?

Rick