Dell Precision 690 Workstation won't boot

Computer worked fine for nearly a year now.  Every once in a while the fans would ramp up in speed and pitch, at which point I'd turn on a box fan in the room aimed under the desk at the computer.  I assumed it was running hot.  Once it just kept getting higher and higher pitched so I powered it off by holding down the power button.  But it has never quit like it did today - it just went into an apparent sleep state that it wouldn't com out of.  So I powered it off.

It has the "4" light on while "off", which from the manual, I see indicates that the computer is plugged into power.  So, that's fine.

But when I push the power button to power up the 1,2,3,4 lights flash, blink 1 3 4, then show 3 4.  "3 4" is not a pattern listed in the Quick Reference Manual (ftp://ftp.dell.com/Manuals/all-products/esuprt_desktop/esuprt_dell_precision_workstation/precision-690_setup%20guide_en-us.pdf) on pages 37-42 under Power-On-Self-Test (POST) codes.  Any ideas?  Power supply going bad?

This particular WS has 18GB of ram and two dual-core Xeon's in it along with two optical drives and two 80GB HD's.   Maybe too much hardware?  A drain on the PS?  But I would guess the 1000W PS should handle it?  Again - any ideas?