I recently aquired a Sigma DR-28. It is a "Made in Japan" model. It appears to be solid wood all around (rosewod sides and back, spruce upper) I have a couple questions for the experts atory on how I aquired it (got it for free)

1. Right after I purchased it I restrung it with Martin Med. strings and now I am getting a Buzzing noise off of the frets when I play. I am new to guitars as this is my first guitar and I am learning on it. What is causing this buzzing noise?

2. Aprox. how old is the guitar?

3. Where can I find a replacement Nut fot the guitar?

Now the quick story. My daughters (3 and 5) are starting to take interest in music one wants to learn Piano, the other drums. So I decided that I wanted to take up a new insterment as well (I play brass and some percusion already) I had a nice CD player I had gotten for free in my car so I put it on Craigs List for trade for a PS 2 or guitar. I ended up getting PS 2 with a few games and some controllers for trade. I played it for a couple days then relisted the PS2 for trade for an acoustic guitar and a guy e-mailed me about this Sigma he had so I went and looked at it and it was in really good shape so we made the trade. My wife and I are short on money so tradeing was the only option I have to get anything. So that is the story

Was it a good trade?   Sorry so long.