Here is the list of components I bought yesterday from a local computer store.

CASE: Coolermaster cm690
PSU: Corsair 550VX
VIDEO: BFG 8800GT
RAM: 2GB of 800Mhz Mushkin RAM
PROCESSOR: e4600
MOBO: Gigabyte P35-DS3L
HD: My own

I assembled the PC yesterday - it was my first build so it took some hours. Now I'm frustrated because the system won't even power up . I followed all of the installation manuals that came with my components. When I finally decided to power up, I plugged in the power cable to the PSU and plugged in the other peripherals. I pressed the power button and nothing happened. I even tried a different outlet in the house but no success.

Please, any help is appreciated.

That could be anything, verify you hooked up the power on button in the case correctly to the mobo. sounds like somehting is not connected.

Ok...let me check this - there should be a seperate wire for the power button to connect to the MOBO?

Do you have all the power plugged into the board... there is an extra 4pin or 8 pin connector that is usually close to the CPU that needs to be connected.
if that isn't the issue then.
Slowly start unplugging things.. Hard drive, DVD, connections to the motherboard (but not power too it cause you need that)
eventually you will have just video card, ram and CPU in the machine...
if it still doesn't post... remove the video card.. you should get warning beeps that it doesn't work.
if still nothing... remove the ram. you should get warning beeps there as well..
remove CPU, should get warning beeps that there is no CPU present...
if still nothing then it can be your motherboard or your power supply.
replace power supply if you can and test.. if still nothing well then it may be the BOARD... DOA

other things to check... is any part of the bottom of the board touching the case? No standoff? or a screw that got lodged underneath..
testing the board out of the case... sitting on the motherboard box is also an idea.

If you have any more questions ... ask away...

Ok thanks for the responses

I did what maximiza said - I somehow forgot to connect the Power Switch to the mobo.

Another problem now - I got the computer turned on, but it makes a high-pitch squealing sound that keeps going until I turn it off.

Is the PCI express power connector plugged into the 8800? If not, that would cause a high-pitched squeal.

http://www.tomswiki.com/page/Troub [...] ild?t=anon

try this, it helped me out my first build.

Gornak was right - it was the PCI-E power that wasn't connected.

Not sure if you know about this case or my MOBO but I think the case can support up to 5 fans the way it's structured. But I can only see 3 PWR_FAN type slots on my MOBO. Additionally the front case fan has a power wire that I can't reach to the MOBO. Each of the fan wires comes with an adapter that switches it to a 4 pronged head and 4 open pronged head. Not sure what this adatper is for... it looks like it could connect to the power slot on a hard drive...

The 4-pin molex connectors for the fans can connect directly to your power supply. Just connect them as best you can and arrange the cables as best as you can to not restrict any airflow.

^ the fans will have adaptors that connect a Molex power cable to the fan connector. The molex is what the older HDD tech uses.
Use the adaptor to plug it in, the only downside is that the system cannot auto-cointrol the fan based on temp.