For Germany to win WW2, Germany would have had to invade Britain and Ireland, not declare war on the USA, then invade the USSR, assuming German defeated then USSR then it would be the USA Germany and possibly Japan in what might eventually become a 'Cold War'
Or Germany leaves Britain, but fending her off, leaves the USSR (for now), this would keep Germany's armies at full strength. Germany could then wait for an Allied invasion, which would be easily defeated it it would remain the size as it was for D-Day, this would leave Germany in a commanding position when the invasion is defeated, Germany could then invade Spain and Portugal, then Gibralter (effectively cutting off the med) German could then invade North Africa/Malta. Once the conquest is complete (which would be easy considering the huge numbers of men and equipment that Germany posseses). With All of Europe and Northern Africa under Germany's control it would now be 'safe' to invade the Soviet Union, Germany would stand a much greater chance now because she is in a much stronger position. If successful Germany would be in a very strong position and would ahve the potential of becoming more powerful than the USA. A 'Cold War' would surely ensure once America comes to an agreement with Germany. This would give America the chance to defeat Japan. Leaving the tow Superpowers to fight it out 'Cold War style'. Hopes this helps
