What's the Startup all about?

So, obviously I'm new to this and really pretty new to the inner workings of computers in general. So, I've downloaded CCleaner and gone through most of the steps.

What I'm wondering is how I would know if I have anything in my startup that is unnecessary and I guess what exactly is this?

Thanks in advance for bringin it down to my level.

Welcome ElkSnout

The documentation is quite good and the Startup programs information is here:

http://docs.piriform.com/ccleaner/using-cc...arting-programs

This information is good:

START-UP APPLICATIONS

DO YOU REALLY NEED ALL OF THEM?

http://www.pacs-portal.co.uk/startup_index.htm

This is also good:

http://www.bleepingcomputer.com/startups

Google is your friend also.

This is also good:

http://www.bleepingcomputer.com/startups

This website is unreal, answers everything.

Thanks for taking the time to help out.