Thanks chepp, but same response.
"The operation could not be completed for 192.168.0.6 for incorrect User credentials."
Slightly more cryptic message, but it do go check the w2000 as I saw the drive light flashing.
I went to the w2000 and created a new account with full admin privileges.
I also tried with the original login name when I first started the pc back in 2004. Same thing. By the way all User accounts have the same password. I tried logging into different ones, even rebooted between, but still the same error.
I tried POCEH suggestion and removed File and Printer sharing and now neither win7 or the 4.0.1 Converted sees it, pretty much as expected though. 
I will go reinstate that.
Thanks for the help so far.