desperatelly need help

I have S2892 Tyan Motherboard Server (2 Opteron 200 Cpu 2X1gig DDR 333 ecc reg Ram - each per CPU - by PQI) power supplyUltra X-connect 500 Wt (20 pin connected thru 20X24 pin transission to m/board and regular 4 pin hdd connector is connected thru 4X8 transition to 8 pin connector on motherboard). This set up was working seemlessly for 3.5 years till my power supply burned. i tried since 3 different power supplies 500-650Wt ranges (Coolmaster 500 EPS, Raidmax 630 and Antec 600). All of them can make cooling fans run and flash LED on the back of the NIC card on motherboard - but no beeps or POST. I replaced motherboard from the case and all connection is done on de-electric plastic bag. Also I check each CPU and memory stick on other workable server S2892 based - to check and proove they are workable. I also got brend new S3892 Tyan Motherboard and tried to boot it up - also no boot. Just d4/d5 code on motherboard LED and no beeps or POST. I already spoke with Tyan support - they are telling me that it seems like boards are demaged. But I still thinks that it is power supply.
Please help: