Untrue. Any PC running any flavor of XP, W2K, or W9x can be made to
network with and share files with any other such PC; nothing hit or miss
about it. In fact, even a PC with W3.11 should be able to join the fun.
And, PCs running NT can also join if using NT v4.0 or later; probably
some earlier versions of NT as well (3.51 seemed OK).
But, not all printers can be so universally shared: some printer vendors
do not support sharing cross-platform (e.g., XP-W9x). Also, some NICs
were sold before their design was completed, so some standard features
just won't work -- IIRC, auto-negotiation failures used to be common.