valutype is the variable to store the data where as 
reference type is the variable to store the reference to 
the data only..Both are derived from the System.valutype.

correction
valutype is the variable to store the data where as 
reference type is the variable to store the reference to 
the data only.Both are derived from the System.object

Boxing

Value Types
Value types contains there data which are allocated on the 
stack or in-line a structure

Reference Types
Reference types stores reference to the value memmory and 
are allocated on the heap and refrence types can be self-
describing type pointer type or interface types.

UNBOXING

value type is boxing and reference type is unboxing