Trying to set up a wired home network, anyone help???

[#1]

Hi All,
i have a desktop pc connected to a modem router 4 port ethernet switch [read that off the box] and my laptop is connected to it as well to access the net.
i set up a shared folder on the desktop of my home pc and a shortcut to it on my laptop desktop in the past and also accessed my printer which is connected to my desktop from my laptop.
all was working fine until one day it said i didnt have rights or something and mentioned being an administrator when i tried to access the folder from my laptop so i thought i would delete it all and set it up again from the 'my network places - set up home network link' which works fine on my pc but when i try and set up on my laptop there is only an option to set up a wireless network and when i put in the xp disc into the laptop to set up the network  it said it couldnt do it as it was on a domain.
my work has intalled a safe boot  program which i have to log onto everytime and also if i leave the laptop for a while, but it was working fine for ages after they intalled that. i never connect to any work networks and i work from home so not sure what to do
both computers are running xp
sorry for the long post but any help would be very much appreciated as its driving me nuts  keep copying to my memory stick or emailing stuff to print or scan.
many thanks
Andy

[#2]

Have you changed your username or password on either of the computers?
Windows is funny. Your username and password MUST be the same on both. If you change your password on one then you're automatically blocked out of the other via network connections.

[#3]

hi, aplogies fo the delay but i have been in hospital, thanks for the reply, i hadnt changed any computer names but i can only think it was to do with a windows update as i also lost all my internet bankng settings, i found the answer below on a pctools forum which worked a treat as nothing else i tried did. posted below incase others get the same problem

Everyone having this problem should follow this...
You must have administrator rights to do this.
Enable the IPX/SPX protocol and follow all instructions.
To enable file and print sharing on the IPX/SPX protocol
Only perform this procedure if your home or small office computers are connected directly to the Internet through individual connections or using a DSL or cable modem connected to an Ethernet network hub.
1. Open Network Connections.
2. In Local Area Network, Right click on top of your connection and select Properties, click Install.
3. In Select Network Component Type, click Protocol, and then click Add.
4. Click NWLink IPX/SPX/NetBIOS Compatible Transport Protocol, click OK, and then click Close.
5. In Network Connections, on the Advanced menu (on top menu bar), click Advanced Settings.
6. On the Adapters and Bindings tab, under Connections, click the local area connection on which you are enabling IPX/SPX file and print sharing.
Under Bindings for Local Area Connection, under File and Printer Sharing for Microsoft Networks, clear the Internet Protocol (TCP/IP) check box, and then click OK.
cheers