"M?ller, Markus" writes:

>What could be the problem here and more important - the solution..?
>Any Ideas?

The symptoms you've shown are typical for bad memory;
have you run some extensive memory checks on the hardware?
The BIOS POST memory-counting is often not enough, there are
free memory checkers available on the net, some of which also
tell you which bank contains a faulty SIMM.

--mkb