Need help replacing old cassette and chain I have an old bike with a cassette and chain that needs replacement.  The problem is that I can't identify what kind of cassette it is or how to remove it.  

There are 14 teeth on the smallest cog and 28 teeth on the largest cog on the cassette.  How do I remove it? There are only two nuts.

Will the bike take any Shimano chain (that matches number of links of the current chain?)




From comment:

I took the wheel off, i watched the video from Parktool but couldn't see any groves inside the cassette
If it's 5 speed, it's probably a freewheel rather than a modern style cassette that slides on a freehub.

Park Tools do a tutorial video on how to change one:


                
            

Additional information can be found on the Park Tools blog