The Q6600 has its days (I have had the Q8200 long ago). I would suggest replacing the whole setup.
1. Some kind of mini-pc (to be discussed)
2. DAS or NAS (not everyone needs a NAS, anyway) to accommodate your HDDs
As #6 mentioned, if your HDDs's capacity are rather small, better get rid of them. For instance, I've a couple of Toshiba 3TB and 2TB.