I just bought parts for a new computer off of Newegg - including an ASUS motherboard supporting SLI (No onboard video!), MSI 9600GT, Athlon 64 5200+ processor, and 4 gigs of RAM.

The first time I put it together, the computer wouldn't start. It would start up, fans and lights flashing, for about a second, then die. After a little bit of internet research, I determined the cause to be a grounding issue, and reinstalled the mobo, apparently fixing the problem. (the lights and fans stayed on after hitting the power button.)

However, after setting everything up and preparing to boot and install windows, I found to my horror that the monitor would not display an image, only informing me that it could not detect a signal. Thinking that perhaps the monitor was dead, I tested it with my laptop video output, and it was fine.

The power supply is fine, all fans are running nicely.

The first thing that comes to mind is a bad video card. Ive tested it on all ports, and in both PCIe slots, to no avail.

Another culprit may be the motherboard: Ive read of some cases where a DOA board will not post. I recall maybe hearing a beep upon startup, but when I try now, I dont get such a response, so it may have been my imagination. Is it possible that during the first time I tried to power it on after building, I fried it?

Is it also possible that the CPU is bad? If so, how could I know?

AT this point, Im really just trying to figure out what went wrong so I can try to return the thing to newegg and get a replacement.

"Is it possible that during the first time I tried to power it on after building, I fried it?"
Yes. If you had a motherboard mounting stud in the wrong place, that 'might' have damaged the motherboard or the power supply.

"Is it also possible that the CPU is bad?"
'Probably' not.

Remove the motherboard and test it outside the case with only the RAM and video card (if there is one) and monitor connected. Note that just because you see 'some' signs of power, that does not meam the power supply is functioning 100%.

I agree about the power supply. Test it by putting the mboard on a cardboard box, then after installing the RAM, video card and monitor (as Aegis suggested), use a screwdriver to short the pins of the mboard that you would connect the power button to.

Hmm I wonder what happened to decency and morality? Doesn't anyone remember them?

No video is usually merely a symptom and there is nothing wrong with your monitor or the system's video.

A common mistake people make these days when they assemble a system is they have bought the wrong ram!

Ram that works in another mboard , or any ram you buy or have lying around, may not work properly, or sometimes, not at all - even if it physically fits and is the right overall type (e.g. SDram, DDR, DDR2, etc.; PCxxxx, xxx mhz) for your mboard. In the worst cases of incompatibilty your mboard WILL NOT BOOT with it installed, and the mboard may not even beep - the ram has to be compatible with the mboard and it's chipset.

See response 5 in this for some info about ram compatibilty, and some places where you can find out what will work in your mboard for sure:
http://www.computing.net/hardware/w...
Correction to that:
Mushkin www.mushkin.com

Once you know which module ID strings work in your mboard, you can get them from anywhere you like that has ram with those ID strings.

It is easy to test for incompatible ram that has caused your mboard to fail to boot.

Make sure you have a speaker or speakers connected to the mboard so you can hear mboard beeps (see your mboard manual).
Remove the AC power to the case/power supply.
Remove all the ram.
Restore AC power.
Try to boot.
If nothing else is wrong, you will hear a pattern of beeps that indicate no ram is installed, or a ram problem.
E.g. for an Award bios or a bios based on one, that's often a beep of about a half second, silence for a half second, a beep of about a half second, silence for a half second, continuously.

If you get no display and no beep with the minimum configuration. Remove the RAM and try. Like Tubesandwires said, certain RAM problems can cause the system to be completely dead. With the RAM removed you should get error beeps that indicate a RAM problem.

Ok, I gave my graphics card to a friend to test, and apparently it worked fine in his computer.

I have tried the RAM thing, removing them from the motherboard, which was in turn removed from the case, but I still don't hear any beeps with or without speakers attached. This leads me to think that it is a motherboard problem.
Is there any secondary wasy to test it so that I may be sure before I get a replacement?

Oh, I also want to mention about RAM compatibility: my RAM, 4 GB of Transcend J4... something or other (sorry, typing from school here) is not on the supported RAM list in the ASUS motherboard guidebook. However, several other models of Transcend RAM are supported, and the fact that all of them have a lower (J3) type number leads me to think that there is a possibility that the motherboard came out before the RAM, though this is merely uneducated speculation on my part. The RAM itself claims to be "100% compatible".

"Ok, I gave my graphics card to a friend to test, and apparently it worked fine in his computer."

As I have already said, no video is usually merely a symptom. Both your monitor and your video card are fine.

"I have tried the RAM thing, removing them from the motherboard, which was in turn removed from the case, but I still don't hear any beeps with or without speakers attached."

That's not good.
Other than the mboard being damaged, the most common reason for that, assuming the cpu is actually supported by the mboard bios, is a faulty PS. In this case, it's also possble the PS was damaged from your "grounding problem".
Failing power supplies are common and can cause your symptoms.
Check your PS.
See response 4 in this:
http://www.computing.net/hardware/w...

"After a little bit of internet research, I determined the cause to be a grounding issue, and reinstalled the mobo, apparently fixing the problem. (the lights and fans stayed on after hitting the power button.)"

You may have damaged the mboard, and/or possibly the PS, if you had a metal mounting post in the wrong place previous to that, or some other situation where the wrong place was grounded. If there is visible damage to the mboard they may reject any RMA claim.

Everthing else has to be okay before you can determine whether ram you bought is incompatible, if it isn't on a list of supported modules somewhere.

The list of supported modules or known to work modules for a mboard model in it's manual or on the mboard maker's web site is often outdated and there are often newer modules known to work fine.
If you are able to find a place where you can look up which Transcend modules work in your mboard for sure by using the mboard model number to search with, preferably on a Transcend web site, that has the newest info and all supported module ID numbers should be on that.
If the module ID string on the modules you have are not on that list, or if you can't find a place with such ac list, whether they will work at all or work properly in your mboard is a crap shoot - random.

In the case of AM2/AM2+ cpus / AM2 or AM2+ mboards, the ram controller is in the cpu itself, and it's the cpu ram controller the ram must be compatible with, not so much the mboard chipset. In theory, any ram for an AM2 or AM2+ mboard should work in your mboard.