These are decent switches. The FSM7352S is a 48 port layer 3 10/100 switch with 4 copper/fiber combo ports. The last two ports are set to be stacking ports by default, and cannot be used for normal purposes.
To disable stacking from the command line:
enable (if you aren't there already)
stack-port 1/0/51 ethernet
stack-port 1/0/52 ethernet
To revert them back to stack ports:
stack-port 1/0/51 stack
stack-port 1/0/52 stack