Deleted files can be recovered if one looks hard enough. Even reformatting doesn't make things disappear completely. It is doubtful that your maintenance dept will run recovery software to look for old, deleted files, so you are probably safe this time.

The problem that you describe, along with other potential problems, (such as your ISP sending a warning to your company about possible copyright infringement), makes it a good idea to not use LW or any p-p software on a company computer.