When I turn on my thinkpad T30 ibm, a black screen with a padlock appears. I tried "merlin" to unlock my setup but it wouldn't work. Can you help so I can log in again?

I've used a free application many times in the past called Ophcrack which searches for all operating system user account passwords. However, this application requires you to create a bootable disc so that you can insert the cd on start up (making sure that the bios boot order has the cd drive as a primary boot device) and allow the program to run. To burn the Ophcrack ISO image onto a bootable disc I would recommend Active@ ISO burner which again is free and very intuitive to use.