How do I restart replication which has failed without re-creating Distribution, Sunscription etc.?

I think you are talking about reinitialize subscriptions:

But why it failed and what was done to fix? 

Could you please explain what exactly you are trying to achieve?

If there is no distribution, subscription etc then there wont be any replication, in which case, you just have to start from begininning,.... I think you are confused here. Please give more details so we could help.

Why has the Replication failed?  Please supply error numbers and messages please.