NP Problems

I am sure most of the computer science students must aware of these

Problems that are also known as Non Polynomial Problems .

Such Problems are those which can not be executed in Polynomial time

infact run time of these problems varies exponentially.Till now researchers

are

continuously working on these problems but they are not successful in solving

these Problems for eg Hamiltonian cycle ,Vertex cover all these problem are

NP or NP hard Problems ?

I want to know about view points about these problems?What you say

about these problems