I am setting up a home network with a PC and a laptop.  Both run
Windows XP, SP2.  Both are able to log onto the internet with no
problems.  Sharing has been enabled on both.  Firewalls have been
lowered to make sure they're not interfering.  I have set the
workgroup to be exactly the same for both and both computers have
unique ID's.  I can see my PC on the network (but only on the PC), but
I cannot get the laptop on, it seems.

I have tried running the Network Setup Wizard in XP, but that doesn't
help.  I tried running my router's software, but that doesn't help.  I
believe I have localized the problem to the Local Area Connection
Properties window in the laptop.  When I open this, it does not have
the "Client for Microsoft Networks" or the "File and Printer Sharing
for Microsoft Networks" checked.  When I attempt to check them and
then exit by hitting "OK", it says, "Your current selection will also
disable the following components: Cline for Microsoft Networks; File
and Printer Sharing for Microsoft Networks.  Are you sure you want to
disable these component(s)?"

(Note: the options currently selected are "QoS Packet Scheduler",
"AEGIS Protocol (IEEE 802.1x) v2.3.0.0", and "Internet Protocol
(TCP/IP)")

So, it would seem the laptop will not allow me to choose these options
because when I do and then click "OK" it disables them.  I believe
there must be some other program running that will not allow me to
enable these options, but I don't know what and I am out of answers. 
I hope you can help.

Are you just trying to share a printer/files? If so, you might be able
to manually add the network place using a wizard in Windows XP.

one simple suggestion get the ip address of the desktop and on the
laptop go to run and key in "\\192.x.x.x"(which would be the ip
address of the desktop ). Try the same on the desktop in run key in
"\\192.x.x.x" (ip address of the laptop") File and print sharing has
to be enabled on both the machines and don't forget to share a few
folders. Also check if these machines can ping each other.(hope u know
how to do that.. :)

I am trying to do file/printer sharing.  I have run every wizard in XP
that I know of (which consists mostly of just the Network Setup
Wizard).  I did ping each computer to the other, and the ping worked,
but still I can't see anything of the Laptop on the network.