I've triple checked the violin.
There are no cracks in the seams, there doesn't seem to be anything in the violin, I don't have a piece of jewelry or anything that's coming in contact with the back of the instrument.
No tuning pegs are loose. The strings are new.
The bridge seems lined up properly.

When did this website get so inactive?
Or is it because no one here plays the violin? I've been playing with the same crappy cheap violin (it came off eBay for $40) for 8 years, so I know nothing about violin maintenance.

This site has always been inactive outside of the sheet music request subforum.

As for the buzzing sound, what kind of sound are we talking about? Some kind of bee type buzzing when you play an open string?

If you already checked the pegs, strings, and bridge, then the only thing I can think of is the soundpost itself must have either cracked or been displaced.

Regardless, if it was only $40, probably not gonna be worth it to have the soundpost realigned/fixed, and your better off getting a new one.