The screen on my laptop (Fedora 7) goes black and it hangs but if I connect a second screen, then this works ok, only the first remains black. This happens at random when opening some regular webpages. Some other time the same pages open without problem.
Also experimented with another pc running MAXIVISTA as a server and the
same Compaq as a client (WIN XP) only to see if the monitor as such could work, then the Compaq screen worked just fine.
So, it must be something on the motherboard, perhaps the inverter chip?
I appreciate any help, I am not good in hardware! HP service told me to
buy another laptop...

If you are like me, you have a vga output on the back of your laptop... this is not dual head: it will run only one monitor at a time. You select whether to output to the tft or the external vga using a fn-key combination. The exact combination varies between machines... with me it is fn+F5 but I've seen it in fn+F6. Have fun.

sorry, you didn't get it. The screen of laptop goes suddenly black and that is why I experimented, to get an idea of what is wrong. It has nothing to do with the multiple monitors option of my machine, which I used for the experiment. In fact there is such possibility for the video board of this laptop and I have used it extensively, inspite your comments.

OK - does your laptop have the ability to switch single-head video between the tft and an external monitor? If so, have you checked this?

Do I understand you that XP didn't run the screen either except when used as a client?

If it is not something like what I have said, then hp is right - it is extremely unlikely that you can service the mobo ... it's tough enough just getting an electrical contact for these things. Have you opened it to have a look?