You seem to be using a very old version of gOS, but that doesn't
explain much, neither that you are "on a LAN".
gOS (unlike windows) doesn't need to be frequently defragmentated, so
there is no defragmentation utility, and it does not explain any
slowdowns.
If you have little memory, (RAM) like 256MB (or less, as that is
possible with E17) then the biggest suspect is too many programs
running at the same time.
If possible add some more RAM.