How can I make my Windows PC/Tablet kid safe? Where can i find a kid safe web browser? How can I hide Windows Apps from my kids on the computer?

I was looking for an Windows application to make my tablet kid safe for my three year old son.  I tried with Microsoft familysafety, which works pretty OK, but did not fully satisfy me, because it still left too many things on the computer accessable (Standard apps like store etc. are still there) and iI found it too complicate to allow access to selected videos on YouTube to him.
I was looking for an application that can be placed in AutoStart under his account, runs in Kiosk mode and hides everything on the computer from him which is not declared accessable by partents. It should like his own little world on my computer with games and internet content suitable for his age.

How-Ifixed-it:
In "Magic Desktop" i exactly found what I was looking for: http://www.magicdesktop.com/en-US/Product

How to make an andorid phone kid safe / Android-Handy kindersicher machen

I was looking for an app to make my kids' android phone more kid safe and restrict internet and app access.

How-i-fixed it:
I found the great free app "Kids place" on google marketplace.
I allows to define a PIN number for administratration and lets you select the apps the kids see on their home screen. It also lets you configure the internet access. I re-routes the home button to the Kids Place home screen and also can be configured to Auto-Start.

I found the right hint to this great app here:
http://onsoftware.softonic.de/so-machen-sie-ihr-android-handy-kindersicher