access user accounts

I'm hoping someone can help. I have and old hard drive from a broke down PC
and I want to retrieve the pictures from it. I have the drive hooked up to another computer. I did this by unhooking the CD-ROM drive and hooking the old hard drive to those cables. I can acces the drive and can get to the pictures on the user accounts that didn't have a password but the Administrator account as well as one of the User accounts had passwords. when I try to click on those folders I get an error message saying "D:\Documents and Settings\Administrator is not Accessible. Access is Denied" I have the passwords to these accounts but how can I get to where I can log on to gain access to these accounts?

any help is appreciated,
Thanks