The Russians did not counter attack until late 1941. The axis had been defeated in North Africa, losing half a million troops killed or captured (a defeat as great as that at Stalingrad) and putting Italy out of the War (
https://en.wikipedia.org/wiki/North_African_Campaign ). After North Africa and Stalingrad they were finished. The USA entered at the very end of 1941 and would have ensured victory even if the Russians had not advanced.
France was an axis power in 1941, fighting alongside Germany and part of the EEC.
http://homepage.ntlworld.com/lee.riley/Notices/EWG.pdfYes, the Soviets changed sides after Hitler attacked them. Probably one of the most insane military decisions in world history. However, once the USA entered WWII the defeat of the axis was a forgone conclusion, it having already been fatally weakened by the British and Soviets.