Sql query for total salary deptno wise where more than two employess exits from the below table (tried lot can any one help me with this)

First off, your data is bad: no department has more than two employees in that data, and some employees appear to be pulling a salary from two departments, which is ... um ... odd.
If you assume that you meant "more than one" employee to a Department, then it can be done very easily.

Start by grouping employees together by department: that's trivial, it's just a GROUP BY statement with a HAVING clause to restrict it to 2 or more employees:

GROUP BY DeptNo 
HAVING COUNT(EmpId) >= 2

Then you can apply your aggregate function to the groups:

SELECT DeptNo, SUM(Sal) AS Total FROM Employees
GROUP BY DeptNo 
HAVING COUNT(EmpId) >= 2

And that gives you the result you need:

DeptNo  Total
1        6000
2        8000