How would I obtain the correct DNS server settings from the wifi router and from the Mac please?
Depends on the router config / setup program - RTFM, I'm afraid.
Ditto with the Mac - there must be a simple network information button, as it's a Mac
It would be useful to check what the IP address, subnet mask, Default gateway, DHCP server and DNS servers are on the Mac. Check also if you can ping the Mac and the wifi router (10.0.0.138).
Once you have the correct info, you can manually enter it into the network settings for the PC.
Here is a useful guide - lots more where that came from!
You can either choose to have a fixed IP address and enter the DNS servers manually, DHCP IP address and enter the DNS servers manually or both DHCP IP address and DNS servers obtained automatically.
Since the last case isn't working, and I don't recommend the second, that leaves you with the first option.
Before you change anything, note down your current settings!
You will need to enter the IP address as 10.0.0.x, where x is any number not already in use (10.0.0.1, 10.0.0.138 etc.), the subnet mask as 255.255.255.0, the default gateway as 10.0.0.138 and the DNS servers as whatever they turn out to be.
husband already threatening to buy a new PC
And that would help... how?
Spending the money on a complete reference library for Windows XP support might be a wiser investment!
SD