How to add WinXP Computer to existing LAN ?

My LAN:
Computer 1: Win98SE, Linksys Lne 10/100 ethernet card; HP Photosmart Printer
Computer2: Win98SE, Linksys Lne 10/100 ethernet card; HP 970cxi Printer
Computer 3: WinXP Pro, D-Link 530+ ethernet card
Linksys BEF41 router
Surfboard Cable Modem
Computer 1& Computer 2 are on the LAN sharing printers, hard drives, internet access. Network protocols are TCP/IP & NETBEUI.
Computer 3 was newly added and has no printer. When I installed WinXP Pro, internet access awas there without me having to modify settings. I enabled sharing of the hard drive and then on computer 3 I can now see and share files with Computer 1 but not computer 2. I did nothing else with WinXP and networking.

Now:
Computer 1 can shares files and its printer with Computers 2 & 3.
Computer 2 can share files and printer with COmputer 1 only.
Computer 3 can share files with COmputer 1.

ow do I fix computer 3 so that it will share files with computer 2 and be able to print on Computer 2's printer?

do you got a firewall installed?

im a boring old fart and a crazy loon.
im also a mad alcoholic git but do that matter!

it's sounding more like hardware. but in order to more easily verify it you might want to test without the firewall and router going to make sure they aren't doing anything wierd.

Did you do a ping from 2 to 3? I believe that is also required to verify a working connection.