96 k1500 5.7 won't start

I've got a question concerning my 96 k1500 5.7.
Just today I turned the key, it turned over faster than normal for a second and then I heard a fairly loud clanking sound. Any ideas as to what it might be?
The truck has been sitting for around 2 weeks since I've last driven it. The starter was replaced back in January at the local shop.....if that could have anything to do with it??.