How to turn off log on Screen (more to it)

Ok I just got a machine from a friend and they want it to be cleaned out of all the busines stuff and just put it so you can do normal stuff. The only problem is that he was given that machine a long time a go and he doesn't remember any of the passwords or anything. So I reasoned that on the machine there was nothing i could really do, so I took the hard drive out and put it in my machine so that at least I could access the files and perhaps get somewhere.

So my question is: Is there any way to disable the Windows login screen by having the hard drive plugged up to my machine?

All i've read is that you can do it using the registry editor but on my machine I can only edit the regestry on my machine.

any help?

Try this page to reset the admin password which then you can remove the user passwords.
http://www.petri.co.il/forgot_admi [...] word.htm#3