If you are saying you can access the Mint machine (icon), but cannot open folders, have you shared one?
I suspect you haven't. Right click on a suitable folder and share it just as you do in Windows and it should appear as a share in Windows.
Generally speaking, Mint is really easy. Let us know if you still have a problem.
Also, make sure Windows has fully booted, as it's network configuration is one of the last things it does and it can be as slow as hell.