Thanks for your help!!
As far as my understanding goes the cable I put in is NOT crossed over right now - I do not know whether it was or not originally as one end went together with the plastering.
The reason I say this is that the patch Fem-Fem patch cable I built has the same ending on both connectors. The two Male-Male cables I am using to connect it to the router and the PC are patch cables with same endings so I presume the overall result is a patch cable. Is that correct?
Having said I'll check any BIOS setting for AutoMDI (didn't see any last time I checked). PC does not work in Vista nor Linux but I'll try to see if Vista has a switch to that effect.
Would definitely buy a switch if this would solve the problem - I am bit hesitant as it adds another box/PSW to the system. Obviously I could also put in a wireless card into the PC.