For The Love Of Hardware - Gypsy Curse Edition

So I bought a fancy 650W PSU that cost more than the graphics card. It would generate plenty of juice, supposedly has a quiet fan and dance a tango.

If it worked.

Which it doesn't. Won't turn on. Putting in the old power supply - it turns on. New power supply? The LED for HDD activity flickers on briefly and then nothing. Zilch. Nada.

I've triple checked all the connections. Same ending.

I'll return it to Best Buy. Card is going back to NewEgg. I'll put the computer back the way I know it works for now.

A 360 as a gaming rig replacement? Looking better and better.