Help !

I have an old iBook wired to a router and a new PC linking wirelessly to same router. On the Mac I have 'seen' the PC but not been able to connect to it.

On the PC, the Network and Sharing Centre lists 'IBOOK'. When I click on this, 'Windows Security' asks me to 'Enter Network Password', asking for User name and password.

I have tried:

1) The user name and password of my admin account on the iBook. This returns a 'logon failure' message but lists the user name as [NAME_OF_PC\User Name], suggesting it was looking for the user name of the PC, not the Mac.

2) The user name and password of my account on the PC. This also returns a 'logon failure' message.

3) The user name of my account on the PC and the 'homegroup password' given to me by Windows when setting up the PC. This also returns a 'logon failure' message.

Today I've tried connecting the two machines via a patch cable - still no joy.

Can anyone help? It is 20 years since I wrestled with any OS other than Mac, and 10 years since I've done mich wrangling with the Macs, so please assume no knowledge!

Thanks in advance,