PowerEdge T105 integrated graphics adapter broken

Dear forum members,

I hope somebody could give me some advice. The integrated VGA (ATI ES1000) gave up, the system gives a long and two short beeps at POST. There is no video output, not even at the BIOS. Apart from this it seems that the operation system loads (I concluded it from HDD activity).

Is there any way to disable the integrated graphics adapter when I add an external PCI express graphics card? Actually I have done it before, and it worked well, but later I removed the added graphics card. Now I inserted it again, but this time there is no video output.

Any advice how can I recover my system?

Thanks,

Laszlo