96 Taurus Starting Problem

I have a 96 taurus LX with the Duratec 24V 3.0 engine. We leave it in AZ for the summer and upon return this year it started ok after we charged the battery but after sitting a couple weeks it now fails to start and makes a metal rattle sound when it turns over. Sound is more on the driver side of teh engine. Almost sounds like a broken chain or belt? Car has 106K and has always been serviced well. I have not seen any info on chain or belt replacement that would indicate this was a risk. Suggestions or ??