drinkability of aged champagne

[GDrew]

Total novice here. Be gentle :-)
1) I have a bottle of Moet Chandon White Star Champagne, that has been in my refridgerator fo 4 years (long, sad story). Now, I have occassion to use it in 3 days, if it is alright. Will it be any good?
2) Second, I have another bottle of the same wine, which has been stored in a cool dry pantry, on it's side, for the same length of time.. wil that one be drinkable?
3) Why is there no vintage date on these bottles of Moet?
Thanks!
Gary