Hello, sometimes you can find a compatibility problem with video cards and unfortunately we don't have a list of compatible or tested ones.
In some occasions, using an older BIOS will help you, but it will be to test to check if one works for you.
The beep tones that you get can mean different things, to check the meaning of the beep tones try looking in to the Technical Product Specification for the motherboard found on the following web site:
thanks for your message. Currently I do use the onboard graphics of DH77KC and have the problems described in my first post. Currently I am thinking about using an additional graphic card as suggested by Horst. Do you know if there is a common problem with DH77KC onboard graphics?
Regarding beep tones I checked the product spec, but there are only beep tones mentioned while booting. As I have explained in my first post the beeps occur if I power off by holding power button long time. And I could not find something about this in prod spec.
i have contacted intel by phone. I think the right bios was something with version 59. With this the pc has runned, but sometimes the screen was black and every time i have switched the screen off and on, resolution or colors have changed or all open windows have moved.
I have used a ATI Radeon HD5670 from Sapphire first and now a HD5870.
I had the problems on the display link port with a 27" screen. I have selected this board, because it supports big screens with the onboard graphic.