EULAs like most standard terms will contain severability clauses which basically say that even if one clause is invalid the remainder still holds...

If France(as is in pretty much everywhere in the EU) any EULA that is accepted by default by opening a product(think MS Windows packaging) is void by default, because courts ruled that opening a package does not constitute entering a legally binding contract,no matter what the packaging says.

Because in France, a judge may very well decide that some part of the contract is illegal but consider that the remaining still holds. That happens all the time.