MS PAINT CAN NOT WILL NOT AND SHOULD NOT BE USED FOR MAKING COVERSRead it. Memorize it. Don't have Photoshop? Here you have 2 free choices.
The GIMP: More features, harder to learn. (I still can't figure it out)
Paint.NET: Although it's not unicorns and rainbows all the way through, I learned it when I was a newbie just like you. It is definitely more simple than The GIMP. If you need any help with it I can try to guide you through a step.
Paint.NET needs the Microsoft .NET framework, which was preinstalled on my system. If it's not on your system (if Paint.NET doesn't open) than try downloading it from here:
http://www.microsoft.com/downloads/details.aspx?FamilyID=0856EACB-4362-4B0D-8EDD-AAB15C5E04F5&displaylang=enMS Paint falls short for many reasons. There is a huge lack of features for one. And the other major issue is that covers here are 300dpi (dots per inch) and MS Paint is only capable of 72dpi, so anything 300dpi looks HUGE in MS Paint. 300dpi is a high quality and MS paint ruins the quality.