OK, you have selected the Folders or Drives (essentially folders) that you want to share. i.e. Right Click on a Folder and Select Sharing (in Windows 2000) or Sharing and Security and the set the folder as Shared?

One minor note in this, to work properly in Windows XP Go, My Computer -> Tools -> Folder Options -> And UNcheck Simple file sharing. Makes things a whole lot easier!

Yes, UNCHECK.

Then voila. Things should work as planned.

Hope this helped

Ok did that,
So these computers are going to be able to see each other even though they are connected directly to the router?
Do I not have to create a network? - because I did that and it doesnt seem to want to work.

Ok, maybe I am misunderstanding. So lets get things clear...

1. Are the Computers Visible to one another in My Network Places?
2. Can you Map a Network drive on either of them?
3. Have you set permissions on the shares?
4. What extactly are you trying to share out? File (which could be put into a shared folder to access), just a folder & its contents? Of and entire drive?

I havent read your problem thoroughly because to do so usually confounds me
I just go for the essence and use the force...
OK I had this problem a few months ago.
You should set up a network and it will do so whether you like it or not as that is the way of windows. Main thing you got to do is decide which one is going to be the primary AND go to the XP box and make XP Network disk... Im not at one right now so I forget where to
look... make the floppy and go to the 2000 box and install it on there. Then the two will have basic comms worked out.
Then go to each and open up console
Start menu->Run->cmd
type in ipconfig /all
write it all down
then type ping (your other computer's name)
write down ttl and all that
go to other terminal do the same
if they cant ping each other by computer name then use the IP
if that doesnt work you need to iron out your network settings on each
if you have an established internet connection on both then DONT MESS WITH DNS
otw you will have a MAJOR problem
routers even linksys are notoriously bad news with dhcp and broadband connects
Ive had more probs than I care to share
Well for now keep it simple and make XP network floppy and install and report outcome
make sure you keep your own physical log of all the numbers etc.
That will help me assess your situation

Also you do NOT need to run one of the computers through the other ...DONT TOUCH the connection to the router whatsoever unless you lose internet connection.
You already have a network running from what i can infer from your description.
The router also acts as a switch and typically will assign IPs within by DHCP
go to Network settings
but change anything yet.
go to TCP/IP Properties and check it out ...should have assign automatically by DHCP
the only values you should have entered in there are for your primary and secondary DNS servers
make notes of all the settings that you see and post on here
you will be able to transfer files and all pretty soon. But I would suggest that you choose an OS for both of them and use that universally as it will simplify things greatly and reduce about 75-85% of your present and future errors in comms and data transfer
take it from me... I once nearly crashed my office network by bringing my home system to work (running XP Pro) which used w2k Pro
personally I suggest w2k for stability but XP has some purty graphics and nifty internal firewall setting :oops: haha
good luck ... I hope the user of the other computer is 'compatible' with the idea of adding an additional OS to their box.
If you decide to do that just make it a parallel installation but name it something (if u can) other than 'WINNT' or 'WINDOWS' ...that will cause most remote scripted hacks and virii to fail their attempts to mess with it ...but please make ERD w/registry and write it down in case you have to do serious recovery work.