although some spyware exists for the Mac, there is not much of it. For it to be installed, person installing it would need to know the admin password of that laptop.
If this laptop is running OS X as the operating system, you/she should have no problem changing the password on her account and effectively locking out any other users.
Can you confirm what OS it is running?
The computer needs to be set so that it does NOT log anyone on automatically when it starts up.

If the web browser being used is Safari, you will find the Reset option under the word Safari, on the menu bar when the program is running.
Details of what each item is can be found by looking in the help file, also on the menu bar, and typing in Resetting Safari.

Once you have give us a little more information about the laptop and the OS that is running on it, we can help you more

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