6 monitors... 2 slip into COMA

I have two Nvidia GeForce 8400 GS, one Nvidia GeForce 8500 GT giving me a total of 6 Video outputs
I have two dell E153fp, one dell e171fpb I have two hyvision 19 and one Samsung SyncMaster 940MW
Configuration went awesome
All the monitors work 100%
Then in 15 minutes when they monitors should shut off they do
Perfection!
I come back and shake the mouse
Four screen light up
I found that if I plug my USB video card in the other two monitors light up
This got old
Therefore, I changed the monitor time out to 1000 minutes
Not much changed, just took longer
I have removed all the drivers, the video cards
Pulled them from the machine and replaced them
And put them all back in as NEW
Let windows seven detect on its own
Reconfigured all 6 again
No change
Went to Nvidia and got the drivers
NO CHANGE
Put each monitor on a different video card too
NO CHANGE
Next?
OH almost forgot..new power supply 600 watts
the room is temp controlled and the machine has good ventilation

thanks for your brains...

OH! it is the same two video ports that do not wake up no matter what the configuration
one from each of the Nvidia GeForce 8400 GS cards both on the secondary ports

I work off two...the other four just show monitoring screens..no hi use videos of major graphics

no another USB device does not give the same results
it only seems to be the adding in of a NEW OR removing the USB video card
and NO there is not screen attached to this card
it was by accident I discovered this

So just for clarification, it's the same port that does not wake up, on two identical graphics cards?

Have you thought about replacing them with the 8500 series, like the one that works properly?

8500 is AGP 8400 is PCI

it is the second port on both the 8400 cards that slips into coma

SVGA on ALL ports

have set the time out to 10000 minutes and just turn monitors off manually now

and the logs are clear...nothing is wrong

anyone new have any thoughts?

ya...I thought so too...well back when it was on a 250 watt PS

so i upped it to the 550

only one hard drive and 2 fans
one on CPU and on case