I could be wrong(seems to happen a lot lately) but sound with no picture sounds like a codec thing to me.
Have you ever used/heard of the g spot codec information appliance
http://www.headbands.com/gspot/
maybe it can help. Here is another thought you said you had computer problems, I remember having trouble
playing some vid types after doing a windows reinstall and update/patch. I don't remember the details but
it had something to do with a smr codec and a hack/patch of a microsoft codec. Does this type of thing
ring any bells for you in your situation ?