Consecutive Integers

[perito]

Im trying to solve this

The prime 41, can be written as the sum of six consecutive primes:
41 = 2 + 3 + 5 + 7 + 11 + 13

This is the longest sum of consecutive primes that adds to a prime below one-hundred.

The longest sum of consecutive primes below one-thousand that adds to a prime, contains 21 terms, and is equal to 953.

Which prime, below one-million, can be written as the sum of the most consecutive primes?

I wrote this code, it should work but it doesnt !
It works correctly for number under 100, but it doesnt even work for numbers under 1000
it gives a wrong answer 281 (it must be 953)
can anyone tell me where im going wrong?

public class ConescutivePrimes 
{
	public static boolean isPrime(int nbr)
	{
		boolean isNPrime=true;
		for (int i = 2; i < nbr; i++)
			if ((nbr != i) && (nbr % i == 0))
			{
				isNPrime = false;
				break;
			}
		if (isNPrime == true) return true;
		else return false;
	}
	public static void main(String[] args) 
	{
		int maxValue=1000,sum=0,lastPrimeSum=0;
		for (int i=2;i<maxValue;i++)
		{
			if (isPrime(i) == true && sum+i<maxValue)
			{
				sum+=i;
				if (isPrime(sum)==true)
					lastPrimeSum=sum;
			}
		}
		System.out.println(lastPrimeSum);
	}
}

change the value of maxValue to 100 and see the correct answer,
change it to 1000 and see it go all wrong... WHY?