I am looking for any solution available in Linux that is able to convert a simple text like this to a block diagram in form of a product tree:

-Computer
--CPU
---power source
---chasis
---motherboard
----memory slot
----video chip
--Monitor
--Keyboard

This mean to output an image file (PNG, etc) or libreoffice draw file or any other graphical result with the graphical version of the correspondence PRODUCT TREE.
This should be automatic because text, hierarchy, order or relation are automatic changed and updated. Diagram should be generated fully automated.

I know that a TEX/LaTeX solution exist and other commercial sophisticate products.
My requirements are to be used for a product tree not as simple as such given, but with ten or more levels and with additional text in the block like definition, notes, etc. The image will be a huge one, that is not importat. A plotter is available :-). Ideal is that text will be converted in additional to SYSML representation of product tree :-)

Any idea/help will be appreciated very much.

Never done something like this before, but check the following:
draw a bunch of lines, and write texts in xfig, and save the file.
You'll see that the fig format stores the line's coordinates, and the text,
and the format itself is human readable.
I can think about a script that makes a valid .fig from the textual information.
(for example CR/LF = add 30 to y coordinates
- = add 30 to x coordinates
and so on)
You can draw boxes, lines, etc, or include images.
After that you can call xfig with paramteres to make a png/ps/gif etc. output.
Or you should look to pygraphviz.