could I ask that you don't post the contents of any further letters in full? Just a simple precis will do, outlining the salient facts.
As bfoc has said, it will help if you tell us exactly what the problem is - I know that there's a dry joint, but which socket is involved?
Before you start threatening anyone with Watchdog/court action etc. it might be an idea to handle the problem in a logical way. Your first recourse is, as bfoc says, to the company from whom you purchased the machine. They have an obligation in law to repair the fault, if it revealed itself within six months of purchase,provided it wasn't caused by misuse. It's important to deal with the right people - you should not be corresponding directly with Fujitsu Siemens at this point, or their appointed agents, although Dabs may well suggest that you do so after you talk to them. Dabs will almost certainly not effect the repair themselves, and may suggest that you contact Fujitsu Siemens, but that's something for them to decide - and not a decision that you should take for them. It's very important to get the procedure right, and to record the events in the correct sequence, and in the correct detail.
I suggest that you now talk to Dabs about this, and see what their reaction is. Talk to them, don't threaten them - they've done nothing wrong, and you must give them the opportunity to fulfil their contractual obligations to you. Perhaps you'll come back to this thread and let us know what happens.