How Can I Protect My Pc From Child's Surfing.

Since I have a new computer I allow my grandson to use my old Win 7 PC to play games and this is causing a few problems. He is only 9 so it is hard to get him to surf safely, he sees a new game and downloads it and sometime nasties come with it. Looking around I see there is something called Sandboxing, can he use the Internet within this program and if so will it weed out viruses etc? I use Malwarebytes Pro and Avast free and keep it up to date but last week got one of those horrible Ransom things and had to clear it which is very boring and time consuming, also very frustrating for the young gamer. Any advice will be very welcome.

 

Deep freeze is a commercial program that will take a snapshot of the system, then when your done, just go back - undoing all changes.
http://www.steadierstate.com/ <-Free
http://horizondatasys.com/reboot-restore-rx-freeware/ <-"Freemium"
Another tool would be Unchecky - if the kid just clicks next, next.. it supposedly stop you from checking the "install malware(s) options"
Last I'd use https://www.opendns.com/about/press...ols-the-easiest-way-to-keep-kids-safe-online/
That should be pretty solid.
You could do a virtual machine for them to run in.. you tube has videos on setting those up.
You can also snapshot the VM for easy recovery...

 

If a person doesn't mind PAYING for it, Sandboxie will do the trick

 

He never said what version of 7. M$ use to have a program called Steady State (hence the Steadier
). I posted that link to Reboot-Restore above.
Here is one more Comodo Time Machine.
http://www.pcadvisor.co.uk/download/backup-recovery/comodo-time-machine-28-123/
Most of these programs are not supported anymore, but they work.

Windows 7 guest mode.. read about it here.

 

Thanks everyone for your help. I have followed Plodr's suggestion and created a limited account. I also followed the guidelines from the video posted by David GP. If these prove not stringent enough the next step will be the Sandbox.