How to troubleshoot this PC?

I changed my busted motherboard for a ASrock 4CoreDual VSTA, then changed my 478 P4 processor for a Pentium D. I have two DDR-333 512MB memory sticks and an NVIDIA 7600gs AGP card. I put everything in place and plug it to a monitor but the screen is just black. No BIOS or anything at all. Tried with a different monitor with the same results. Tested monitor with another PC and it works perfectly. Tried booting with 1 RAM stick or none at all, same results. My case speaker had a broken mole, I used two other different moles to be able to plug them in, but I don't hear any beeps (i hear a couple of pops when I boot). Everything in the case seems to run fine mechanically, all fans spin, DVD-ROM opens. I reset the bios by using jumpers as indicated in the manual, no change. Video card was working on another motherboard right before I changed it (it's almost brand new) I don't believe I damaged any parts with static or anything similar. What else could it be?How to troubleshoot this PC?
it's really hard to say, based on the info you've given...



1. it's not your monitor

2. it's not likely the power supply



which leaves us with, cpu, graphic's card and RAM...



the ram that you have is pretty slow, old and it's single channel, this could be your problem...try some other ram, higher speed and ddr2...if I had to guess, I'd say that the RAM is your problem...even so you should be getting beeps from your BIOS to indicate this or some other problem, hence your speaker might be busted or hooked up wrong?



try to use on board video (if your mobo has it)...



2x check the jumpers



check the cpu and fan...are they seated properly?...do you have too much therm...grease?



clear the CMOS..battery out...wait 5-10min...switch the clear CMOS jumper...battery back...jumper back...try to boot.



if this doesn't work, repeat but this time download the newest BIOS from the mfg. and flash the bios with a disk or mem-stick after you clear the CMOS.



to really trouble shoot it, you'll have to break it down to bear-bones...disconnect everything but 1 stick of RAM, video card (if no onboard), cpu and fan...just the basics to get into the BIOS...



one by one check all of the DIMM's with one stick and then the other, trying to boot from each after each move...



do you have an, additional power connection for the CPU, 20 or 24 pin main plus another 4,6, or 8 pin right by the cpu for power?How to troubleshoot this PC?
Can you tell if the MB is getting power (lights)? The first trouble shooting signals come through the PC speaker as beeps so if the motherboard and processor are working and getting hung up at a video card you should be hearing beeps from the little PC speaker. Pops do not sound good. If you are not getting a good setup to the PC speaker just disconnect it to make sure it isn't causing a problem. Can you just get a PC speaker from another case? Try reseating everything and remove any add on cards/drives and see what happens. Go completely bare bones and listen to everything to see if it is all hitting and getting power. If it sounds ok add things one at a time and see how it goes. It sucks when you have to wonder about the PC speaker.