Stuck in Reboot Loop

I'm not very knowledgable about computers first of all so please be gentle ;) I have a Dell Inspiron 620. My kids are using this computer for their games and I am using it for social media. A few weeks ago it started having problems...meaning it took forever to load a page. I figured it might have been because of one of their games and whatever  Substitute character removed as per TOU> (excuse the term) downloads with them sometimes, so I tried to restore it to an earlier date... Unfortunately it couldn't find a restore point, so I tried to fix it with start up repair... After hours of working on it it restarted and is now stuck in a loop... It says that it cannot repair the computer automatically and gives me the option to finish...when I click that it shuts off and reboots to the same exact message...over and over and over.... Help, please :(