What OS are you running? Have you got the right drivers for that OS? Is it the same OS as on the old computer? In particular, have you moved from Windows 98/ME to Windows 2000/XP/Vista? parallel port scanners are pretty old nowadays, I had an Agfa one about 7 years ago, it never worked properly with XP, kept vanishing. I think you may have to bite the bullet and get a modern scanner. That Mustek was a new model some time around 1996!