Wrong Workgroup

A small Windows2000 network was once under the workgroup name of HKSSS. Time passed and the PCs were reinstalled with XP under the workgroup name ‘WORKGROUP’. One however was upgraded because of the data on it and the workgroup name was changed using system properties. The problem is that when you go into my network places and select ‘view workgroup computers’ it takes an age and then reports that ‘HKSSS’ cannot be found. There seems to be nothing in the windows registry or anywhere on the harddrive that relates to ‘HKSSS’ or indeed ‘WORKGROUP’ so where is this information held and how do I remove it???