newly built computer wont turn on

[spitfire]

Hi, i built a new computer but it doesn't turn on. I'm using the processor, hard drive, video card, and two disk drives from an eMachines computer. PSU from that computer failed and it took out the motherboard as well. So I ordered a few new parts to try and build a new computer but once I assembled it wouldn't turn on. I press the power button and nothing happens. Also i turn the power supply on it makes a strange high pitch noise which didn't occur when i tested the PSU outside the case. It only occurs when i have it connected to all the components.
I checked several times the connections and they are all connected correctly.
Does anyone have any suggestions on what i used do?
Computer Specs:
Rosewill TU155 midtower w/Rosewill LC-8400BTX 400w PSU (new)
1GB memory DDR1 400MHz pc3200 (new)
PC Chips SiS746FX M848A v5.0 socket A motherboard (new)
AMD Anthlon XP 2400+ processor (from prev. comp)
48x Max CD-RW (from prev. comp)
16x Max DVD-ROM (from prev. comp)
60GB HD Ultra DMA/100 (from prev. comp)
Ti4280 BFG Technologies video card (from prev. comp)

[squall_01]

Sounds like the power supply had went bad.  Wait for a comfromation.

[Crafty]

I also would suspect the PSU. When you say "nothing happens", are any of the fans spinning in your computer when you switch it on? Are you also sure that the whining is coming form the Psu?

[homer]

this needs some clarification...

I press the power button and nothing happens.

i turn the power supply on it makes a strange high pitch noise

you just said nothing happens. please clarify.

is the motherboard front I/O panel hooked up correctly?

[Crafty]

this needs some clarification...

I press the power button and nothing happens.

i turn the power supply on it makes a strange high pitch noise

you just said nothing happens. please clarify.

is the motherboard front I/O panel hooked up correctly?

That's why I asked him if any fans where spinning!!

[spitfire]

well, i guess the whinnying is something, which occurs when i turn on the psu while its in the case and connected to the computer components and i do believe its coming from the psu, but i took the psu out to test it and it works just fine.
Now, when i press the power button to try and turn the computer on, nothing occurs, nothing beside the whinnying. i checked to make sure the power sw, power LED, reset sw, and the HDD LED wires are connected correctly and from what i can see they are connected correctly.
this is leading me to believe that its probably the mobo, i must have mishandled it while i was installing it and damaged it, fortunately it wasn't an expensive mobo.
i'll check all the connections one more time to make sure.

[spitfire]

as for the psu fan, it was spinning when i tested by itself. when i connected all the computer components and tried to turn on the computer no fans were spinning, just a whinnying noise.

[Frankie]

Disconnect all peripherals/adaptors and the systemboard - Does the fan spin now? If yes, reconnect the system board only - Now does the fan spin? If no then the system board is faulty. However, If the fan is still spinning shut down then try connect one device at a time. When the fan stops at a device you connect, then that is the device that is faulty. Let us know!!

[GX1_Man]

And what testing did you do on the CPU which was on the motherboard when it was damaged?

[spitfire]

the fan does not spin when the system board is connected.
as for the cpu i am assuming that it works just fine because it doesn't look damaged or have any broken pins but it is possible that the cpu is faulty. unfortunately i do not have a known good cpu to test on the motherboard or a known good mobo to test the cpu, but i'll see if i can get some known good parts from some friends.
thanks for all your help. 

[Frankie]

the fan does not spin when the system board is connected.
as for the cpu i am assuming that it works just fine because it doesn't look damaged or have any broken pins but it is possible that the cpu is faulty. unfortunately i do not have a known good cpu to test on the motherboard or a known good mobo to test the cpu, but i'll see if i can get some known good parts from some friends.
thanks for all your help. 

Then it sounds like it's the mainboard or Cpu. That is if you disconnected everything I said before you plugged the Psu into the mainboard. Everything that is apart from the Cpu and ram for obvious reasons.