Outlook very slow

I am having a problem with one of my users Outlook 2000. When he goes to attach a file from the network share, outlook seems to freeze and files in that folder start showing up one by one very slowly. The PC itself is one of the latest ones. I triedto attach the same file from somebody’s else PC and it worked fine. I uninstalled and reinstalled Outlook and it is still the same. The OS is W2K Pro. The network is WinNT/W2K. Is it something wrong with the PC browser !? Just in case I stopped and restarted the browser service at no avail.
Any suggestions will be appreciated.
Thank you