Weird problem

[Demon2k3]

I'm having some troubles with my motherboard in my computer. Sometimes when i turn off the computer the motherboard resets itself to it's original state.

The spec is
Asus A7V880 motherboard
Amd Barton xp 2.8ghz processor
400 watt powersupply
Ati radeon 6600GT 256 Mb ram
512 Mb ram

.
basicly what happens is that the motherboard degrades the processor speed from 2.8 to an 1.8 Ghz. and when i try to reconfigure the settings the computer won't boot up. but when i run on an lowerspeed
this is my normal Bios setting

V-core voltage 1.75V
Cpu multiplier 12.5
and clocking is manually set at 166
this sets my processor to 2.8 Ghz

Atm i'm running on
Cpu multiplier 12.5
clocking speed 133
v-core 1.75
This setting gives my processor 2.0 Ghz

so any idea of what this can cause?
i'm thinking it can be
Bios battery
power supply

any help is welcome

 

[Ingafgrinn Macabre]

A barton doesn't exist in 2.8 GHz. You're frying your pc. What your mobo does is to prevent you from foobarring your pc.

An AMD Barton 2800+ runs on 2086 MHz.

 

[Demon2k3]

what i meant was that i run it on 2800 and on 2.08 usually, as it should be, can i prevent the motherboard from reseting by chaning an setting?