It depends on the Widows version she had installed on the PC, because if it's anything other than Windows 8 or Windows 10, it's no longer supported by Microsoft, making the operating systems unsafe to use. In theory, PC Matic will find outdated drivers as well as applications and advise you to bring them up-to-date, but doesn't help with Windows updates. If you have XP, Vista, or Windows 7, so I recommend installing a newer operating system from scratch. On the other hand, if you have a licensed Windows 8 or 10, they will update themselves automatically (without requiring a third-party application).
Also, on a personal note, I don't trust these so-called "system optimizers" that much as in most cases they create more problems than they solve and the price that you pay isn't worth the almost unnoticeable performance boost that you usually get from them.
However, in case you want to find out exactly how PC Matic can help you, and what it can do for the computer in question, I recommend contacting the company's support desk: http://www.pcpitstop.com/support/ as they will surely answer any question you may have.