Can I get into an "abandoned" user profile on windows 7 without the password?

Run command prompt as administrator from your profile. (Windows Key + X gives you a menu which allows you to choose this.

Let's assume your wife's profile name was Tiffany.

net user tiffany NewPass

The new password for her profile would be 'NewPass' Syntax is

net user useame password

where password is the desired new password. Press enter and you can now logout and login using her account.

Here are some additional usages of the net user command as well as the above command.