This is from the site dotnetbull. I am blogging this here for future reference.
|Interface support multiple implementations||Abstract class does not support multiple inheritance|
|Interface does not contain Data Member||Abstract class contains Data Member|
|Interface does not contain Constructors||Abstract class contains Constructors|
|An interface Contains only incomplete member (signature of member)||An abstract class Contains both incomplete (abstract) and complete member|
|An interface cannot have access modifiers by default everything is assumed as public||An abstract class can contain access modifiers for the subs, functions, properties|
|Member of interface can not be Static||Only Complete Member of abstract class can be Static|