[newbie] How do I change linux IP address?

[David Thompson]

    While playing with IP Configurations on my Pentium 90 MHz machine with
Linux version 7.0, I can no longer "ping" my linux server from my client
computers.  How can I verifiy the server's IP address, and change it, if
necessary?  (You can probably tell, I'm VERY newbie).
    I don't even have Samba server up and running, but am trying to assemble
this system little by little as time allows.  Sure appreciate any advice.

TIA,
David Thompson