Vostro 470, keyboard failure, can't get into the bios

I have a VOSTRO 470 PC

=> i7-3770 @3.4GHz, 2x 4GB DDR Ram

Since yesterday after restarting (power up) I get an Error-Message from the BIOS "Keyboard Failure".

The system don't respond to any key pressed.

- I tried all USB-Ports on the system
- I tried different keyboards

no reaction!

It seems like the BIOS has switched off all the USB-Ports.
The keyboard isn't initialized, the leds on the keyboard don't blink after power up, but 5V on the USB-Port are aviable.

I tried already:
- disconnect all peripherie devices like (HD, CDRom, WLAN-Modul, PCIE Graphic-Card)
- removing the CMOS-Batterie and clean the NV-CMOS-RAM by the jumper
- reset the BIOS-Password by jumper (although no password is installed)
- swapping the two banks of RAM
- removing RAM and reinstalling it
- unsing only one bank of RAM
- using other RAM-Slots on the mainboard
- using other RAMs (from a second VOSTRO 470)
- measure all Suppy-Voltages from the power supply (+3.3V, +5V, +5V Standy, +12V)
- change the Power Supply (from a second VOSTRO 470)
- removed the processor from it's socket an reinstalled it

After cleaning the cmos-ram I get a message:
keyboard failure
RTC is reset, BIOS Setup defauls has been loaded.
Strike the F1 key to continue or F2 to run setup utility. (but how I should do that)

Sometime the BIOS shows a message for about 1 second:
Alert! Previous attempts at booting this system faild at checkpoint 00D7. For help in resolving
this problem, please note this checkpoint and contact Dell Technical Support.

! ! !

* I need a possibility to reset the BIOS-Parameters
* or I need a possibility to flash a new BIOS (without keyboard)
* or I need a possibility to reprogramm the BIOS directly on the board - may by by a jtag interface ..

! ! !

Regards, thanks a lot
Robert