File Server

I have a file server setup with linux Samba (Mandriva 2009) we have 8 computers in the office on DHCP we all get booted of the server when someone is transferring big files, burning files directly from the server or working on a big file size document. Here is the specs for my fileserver:

– 2,000+ AMD Athlon XP 1.67 GHz that was turn into a Linux Samba (Mandriva)
– 2x 500GB Hard drive

Is there component or parts to upgrade for our fileserver in order for it not to kick us off when to much data transfers???