Weird Bios Problem

Mb is an Intel D815eea Xp Pro
Put this unit together a month ago
Has the latest bios P11
Has ran fine
It has Intel Ac 97 on board sound
This morning I lost the sound
Checked and it said no device was installed
Device manager showed an error for AC 97 codec
Un & reinstalled no good(tried realtek same)
Then I rebooted to go into bios
And on the boot menu right it finds the cd(normal to that point)
I get the error message
"Illegal AC'97 configuration
Ac'97 Modem fuction disabled"
There it stops unless I go F1 to resume and it boots normally
Or F2 and go to the BIOS
I do not have a modem and none shows up in the device manager
I reinstalled bios, took out cmos battery cleared bios turned off onboard sound stiil same error( no on board modem) onboard stiil same error
Put in a sound card no problem and there is no Intel ac97 audio codec showing in the device manager
But when I reboot I get the same error so I preess F1 and it stars and runs good. 500 watt ps 1gigP3 runs cool 37C.
No answers At Intel or searches
i dont mind having a sound card but I would like it to Boot all the way
Thanks for your help