Completely new to this...

Okay so here is my deal I have an older laptop an HP G71-449WM its a good laptop and I wanted to add a new operating system to it that's a little more secure I have heard good things about Linux and Ubuntu but I just don't know were to get started or what to do how it works or anything I have done a little research and it looks like it takes a lot of work and needs constant attention I just want to find out if its worth the time to do and if so if there is anything I can do to learn the basics and get started if there is anyone willing to give me a hand or just willing to discuss things with me that would be great. thank you.