DON-
You would be able to still operate the computer without knowing that
administrator account's password as long as any other user accounts didn't
have a password attached to them that you didn't know. I would however highly
suggest you do a few things here:
First, if you want to access the administrator account, download Hiren's
Boot CD (
www.hiren.info/pages/bootcd). The CD includes a program to unlock
any account under Windows and reset the password. You would then be able to
access the administrator account.
Second, and probably most important, you need to go and buy yourself a copy
of Windows, and repartition/reformat the drive. I would NEVER use a computer
from someone else without a clean copy of Windows installed on it. You NEVER
know what garbage could be installed on there as far as viruses, malware,
spyware, ect... Also, I am sure that the company probably had a lot of
garbage running in the background that you have no need for. So, get yourself
a copy of Windows and do a clean install. Hope that helps!