Antec Sonata PSU dead

[Gravija]

I have an Antec Sonata w/380W trupower
I have an NF7-S 2.0 newly RMA'ed from Abit, so it should be in fine condition
Now, my problem is that the thing won't boot anymore and i think its a PSU problem, these are steps as to what i did after reapplying AS3 to the CPU after getting the MB:
1. Outside of case, connect everything (video, ide, fans), then proceed to boot using the USB keyboard
2. Video is OK, computer gets to bios screen, then seems to freeze, nothing works, not even reset button, main power goes off
3. Checked connections, turned PSU back on, tried to boot up, but nothing happened, everything looks powered up, but there is no video
4. Repeated step 3 twice, then booted it up and absentmindedly switched keyboards while PSU was on
5. After switching, nothing happened, upon another bootup, the keyboard was taken out whiel PSU was on->
6. TWO-tone beeping sound comes out from front of case (near the bottom, where the hDD racks are)
7. Power switch goes off, checks connections, powers up again, two tone sound occurs, repeated twice or thrice, each time everything looks powered up for a few seconds, then the sound hits and then everything's power gets cut off however the red power light on the NF7 is still on.
8. After the second try, the sound cuts in quicker and the PSU dies faster, and NOW it just doesn't do anything, although the red light on the MB is still on

Can i conclude this is a PSU issue? Can i just replace the PSU? what is the warranty on the antec sonata?
^before my dad is willing to buy another PSU or case he wants to see whether it is really damaged or if i can get it replaced^
also, what are some steps i can take to test the otehr parts (besides putting them into anotehr system, because both my brother and i need that one for schoolwork, however, the specs are nearcly the same)
thanks

 

[Baronz]

Did you try switching out sticks of RAM? What about trying different video cards and taking out all the PCI cards?

Though It sounds like it could be the PSU.

 

[Gravija]

i tried different video cards (9500pro instead of 9600pro)
switched from OCZ PC3200 to mushkin PC3200 (both have been tested in teh working comp)
no PCI cards

 

[jcwagers]

Do you have any friends who would have an extra power supply that you could borrow? That would tell you rather quickly if it was a power supply problem. It would be kinda tough to tell for sure but even a small 250 watt power supply might be enough to boot you into windows to see if that is your problem. Just make sure you keep those PCI cards and everything out that you don't need. If bad gets to worse, try to take it to someone who has more parts than you do or take it to a shop. A shop shouldn't charge more than 20 bux to check that for you. Some of them might even check it for free. Just tell them that you suspect that you have a faulty power supply and see if they'll hook one of theirs up to your system and see if it boots up. Keep us posted and let us know what you find out.

jc