Where Can I Get Websites That Let Me Into Web Sites On A Computer That Have Been Blocked By My Mum?

You can see internet explorer to know which websites have been blocked by your mom. As internet explorer allows you to block websites and you can also remove those websites from the list of block websites. Follow the following procedure to know about blocked websites.
(1) Right Click on your internet explorer icon and select property.
(2) You will see seven buttons on the top of the window which will be open when you select properties.

(3) Click on the security button.
(4) You will see four options here as internet, Local intranet, trusted sites and restricted sites. "Restricted sites" is the area where you can see the list of blocked websites.
(5) Click on the "Restricted sites" option and then click on the "sites" button. Here you can see the list of blocked websites and you can also add websites which you want to block. You can also remove a site from blocked list.  
When you want to access any website that has been added into the blocked list then internet explorer will not allow you to view this website. Similarly, if you are using any other browser like Firefox then you can also restrict websites from opening into browser.