New computer won't even reach BIOS

Hi guys I am new to here, hoping someone can help me out.

Bought a new computer in anticipation of SC2, but things are off to a shaky start.

Components are
Case - ANTEC Sonata III
PSU - Included Earthwatts EA-500D (500W)
CPU - AMD X2 555
GPU - ECS Nividia GT240
RAM - Kingston KVR1333D3N9K2/4G (2x2Gb sticks)
Mobo - ASUS M4A78LT-M LE (1.01g)

Earlier today I had a Gigabyte G-B MA74GMT-S2 (1.0). I plugged everything in and started the computer up but although fans spun, nothing appeared on the monitor (i.e. it wasn't making it even to the BIOS).

Checked out the Gigabyte site and it turns out that that mobo doesn't support the 555.

Proceded to buy the ASUS mobo, seeing on the site that it supported the 555, but here I am with the same problems. On the site it says that it needs a certain BIOS version to work - does this mean I have to get another cpu to boot the computer and update the BIOS and then use my 555 cpu?

Or is it possible I am barking up the wrong tree here. Just want to see if anyone had had CPU incompatibility issues as well, before I start looking at other things. Also, i've been working with Macs the last few years, so I might be missing something, but nothing seems to have changed dramatically.

Any troubleshooting advice would be awesome.

Thanks in advance!!

Murray.

The PIIX2 555 has been supported since the original 0211 BIOS release in 10/10/2009. Check out mdcomp's "Help My Pc Won't Boot!" Troubleshooting Guide at the top of this forum...

http://www.overclockers.com/forums/showthread.php?t=266936

Thanks for the quick response Redduc.
I checked out that guide earlier today, and just wanted to make sure that there was nothing obvious i was missing before I followed it.
Not sure where you found that date, but it is handy to know, as the manual says it was printed in September 09 (i.e. the board might too be from september an have an earlier BIOS, presumable the 0203 one)
Is there any way to know what BIOS my board has without it booting? Or are there any symptoms of a BIOS not supporting a CPU that might identify that as being the problem?
Looking at what version of the BIOS is needed for certain CPUs, i don't understand how this isn't a huge issue for a lot of people.

According to the Asus support site, BIOS v0211 was the initial realease. Unfortunately there's no way to tell which BIOS revision is installed without at least reaching the POST screen. Make sure that in addition to the 24-pin power connector the 4-pin ATX12V (top LH corner of the board) is also connected via the PSU.

Welcome to the Forum! http://www.ocforums.com/showthread.php?t=491697 muzaaaa

Maybe be shorting out on the case?

Whoo thanks so much Redduc you've saved me time and money - it was the 4 pin connector. I dismissed that connector thinking it was there to power a GPU incase your PSU didn't have that connector or something.
Connected it and it boots fine. I wonder if my Gigabyte mobo would have worked...

Also Ondboarder, I have been benchtesting, thanks though.

Eternally grateful, ciao