ASUS M4A88T-M LE Failure to POST

Sigh, this is my first build and it is failing to POST. I have read the excellent tips and am down to a PSU, CPU & MOBO.

Here is the system.
Mobo - M4A88T-M LE
CPU - AMD Phenom II X4 945 Deneb 3.0GHz Socket AM3 95W Quad-Core Desktop Processor HDX945WFGMBOX
Cooler - Stock cooler with artic silver paste
PSU - COOLER MASTER eXtreme Power Plus RS500-PCARD3-US 500W ATX12V v2.3 Power Supply

Here is the Troubleshooting I did
1. Verified no bent pins on CPU
2. Verified minimal paste was on the CPU - no bleed over to the edges
3. Verified CPU lock was engaged
4. Verified Cooler lock was engaged.
5. Plugged in 24pin Mobo power. This is a two part connector (4 + 20).
6. Plugged in 4-pin ATX12V CPU power.
7. Mobo "power' LED was illuminated.
8. Neither PSU nor CPU fan was spinning.

Then Disconnected all PSU cables. Trying to confirm PSU is good.
10. Plugged in Paperclip between Green & COM on 24 pin connector.
11. PSU fan spins up.
12. Measured all voltages on 24 pins. Matches Mobo manual except -5V (e.g. negative 5 V) pin in location 5 was not populated.
13. Measured 12V on ATX12V CPU connector.
At this point I think the PSU is providing proper voltage on connectors except for -5V. Not sure if that is used.


Then I tried a few other things.
14. Plugged in 4 pin connector on the 24 pin connector. CPU fan & PSU fan spun up.

None of these actions led to a set of beeps on the system speaker.
Any further tests welcome. I suspect the Mobo.....