Utilization of Memory and network

I have Netware 4.2 Small buisness for internetware installed.
users are finding difficult in accessing files through client PC.
I would like to check for utilization of memory
in my local server.
How can i check how much memory is being utilised by my server
in order to know whether it is memory related problem or network problem, how i can troubleshoot
this problem
kindly help me out, urgently.
regard
akhtar