I see the real problem that your computer is not set up to allow safe Internet searching. I don't see how putting a password on will really resolve that problem. Totally inappropriate stuff can come up even in response to very appropriate searches and having a parent there isn't going to stop that. It takes about a minute to set Google to "strict" searching. I can't say it will get everything possibly inappropriate, but in our experience it works to get nearly everything. Also, I would suggest installing adblocker. It is free. Whether it is assigned in school or not most kids are going to be able to search at some point.
