Switching from ms-sql to mysql

I have a .bak from a old database which was running off ASP it was given to me by my clients web host when they shut down the old site. Basically I need to find a way to take this .bak file and convert it into a .sql or find some way of having an importable file that I may import into mysql using phpmyadmin.

I believe the database was from MSSQL if not then it had to have been access but I believe access ouputs .MDF files not .bak therefore I’m thinking MSSQL. I’ve searched all over the internet and cant find any solid information. I keep running across sentences that begin like this

“if it was saved from a MySQL database then…” - well it wasn’t so their advice is of little to no help to me.

Best bet is to restore it to a MSSQL database then see about exporting the data in a more fungable format than a binary sql server backup file.