How do I reformat and make partitions on a refurbished computer with windows 7 pro?

I just got this "new" refurbished computer from comp usa as a valentine's day gift and it's pretty awesome (considering I had no computer of any kind for quite a long time before this! and I would like to totally reformat it and start completely fresh with it. :-o And maybe make it into two partitions? I have heard it helps make the computer run better? It's 700 gigs and it's running with windows 7 professional. It came with a cd too called "Windows 7 Pro for Refurbished Computers". I have everything I need But I would like to give it a clean slate and start totally over. Right now it's got comp usa as it's computer name and all it's settings are from the store that refurbished it. Even the network is already named by comp usa. I know these are all settings I can change but I would love to just totally erase the whole drive and start over. I kinda feel like it's somebody else's computer right now. LoL! See, I am used to starting over with a new hard drive... or reformatting it ..and then putting a clean fresh install of the OS onto it and going from there. But I have never used windows 7 before so I am unfamiliar with it. I have no clue how to reformat this computer now. Or am I being stupid for wanting to reformat it? Should I just leave it alone?

It's all one partition right now.

Any suggestions on how or if I should do this?

Thanks!