Hi Again,
Well good news

I have got out the Lan Card & Sound Card and thus using the onboard Lan & Sound. It is now working perfectly, the problem has not turned up since then, and it has been about 4 days now.
I also substituted the RAMs from their primary position (in the blue slots for Dual-Ddr to the Black Set). I will now experiment a bit and try to solve out what the real problem was, eighter the Sound Card itself, or the PCI slot, or the RAM maybe when put up in the Blue slots :|
Anyway 10x for the Support.
Cya