We have a laptop at work that was never put on the network by my predecessor. It's running Windows 7. Basically, the person who used this laptop has now left and moved abroad. As he was the only user of the computer, nobody has his password, and there is data on there that is important and vitally required. I am trying to log on as Administrator, but when I boot into Safe Mode, the Administrator icon is not there as I'd expect. So I thought I'd try and boot into Safe Mode with Command Prompt, and run net user adminisrator /active:yes. But I'm still presented with the normal welcome screen with just the one user icon, so can't do that either. Can anybody give me any ideas how I get the administrator icon so I can logon?
You shouldn't need to. Get your mits on a Linux bootable disk or USB stick and just access the hard disk directly. If it were Windows XP, you could also install the packages (or get them for free in the case of Backtrack and similar security testing distros) "john", "samdump2" and "bkhive" - samdump2 and bkhive extract the usernames and password hashes into a text file, and john cracks the one(s) you want. I'm not sure if Windows 7 is also as vulnerable (it took john 0.00 seconds to crack a weak password on a machine I was recovering), look it up. But if you just need the data, you don't need a password unless the user directory is encrypted, just access the filesystem as normal.
By the way, you might be wondering why I'm telling you guys how to crack a Windows password. It's not because I want to see rampant abuse, widespread chaos and the lamentations of your women. No, I consider it quite important that people are aware of just how secure or otherwise their password is. I'd recommend you try cracking your own password using the above utilities - if you succeed, choose a stronger password and/or protect your computer from unauthorised boot-up methods (BIOS password and boot order should do the trick). There's a reason for the proverb "physical access is total access".
Incidentally, john works for Linux passwords too. It's often used in professional situations to attempt to crack passwords when people set them: if it succeeds then it rejects the new password as "too weak".