what is the command to take ownership?

Can anyone tell me from the DOS prompt, what is the command to take or change the ownership of a file or folder? Thanks

I dont think that Windows XP has any built-in commands to do that. But you can always check the aticle on "How to Take Ownership of a File or Folder in Windows XP" below:

http://support.microsoft.com/kb/308421

Thanks for that but I have tried the gui method in Windows Explorer but it was not working. I have tried from the parent folder also but for replacing permission, owners of files and subfolders, the file in question is read only on a standalone XP SP2. I think that I have to install the optional admin package for xcacls or setacl or something?

You can check the below microsoft article to enable the security tab:
http://support.microsoft.com/kb/290403/en-us

After editing the registry, you must be able to take ownership through Security > Advanced > Owner, if logged in with proper permissions.