Installed twice?

Hi all...
I'm helping a friend out with her son's laptop and the problem seem's to be somehow he's has got two installs of the same copy it appears.
This is my first time ever seeing windows 7 let alone this kind of problem.
I didnt think being able to install the same copy twice was possible but I think I might have been wrong!
Anywhoz...
When I start the laptop it tells me there might have been a hardware change or something that is causing an error and it shows "windows 7" listed twice beneath it, then under that it has a "Tool's" option with a diagnostic tool.
I did a bit of research and tried booting from the CD to repair but it just gets to a certain point then hangs forever with no change, just the back ground screen.
I have permission to wipe it clean and do a fresh install but the problem is I cant get far enough into windows itself to format.
Im gathering that her son got to where I am at now and hit the "install" button instead of repair and somehow installed another copy ...I have no idea!
I'm stumped....any ideas?

Hi barefoot!
Yes I can wipe it clean....its actually a brand new laptop so theres nothing she wants to keep.
I have all the CD's that came with the laptop but when I try and repair, restore, start windows it keeps looping the "boot options" and goes no further.
Now before I go and wipe it clean will I be able to reinstall with the CD's I have?
I no nothing about windows 7 (yet) and XP was SO much easier to just reformat and reinstall :/

I will take a look at those programs and see if its what I need...thanks alot!

P.S. last night I tried to reinstall, go as far as "set up is starting" and it hung there for over 2 hours and did nothing else....right now it just keeps looping "windows error recovery"

Grrrr!
Ok well, its not letting me do ANYTHING with the windows CD!
Just keeps getting stuck after I select "repair" option or "reinstall" option!

This is definitly not how I wanted my 1st experience with windows 7 lol!!
Guess ill just let it sit here and hang where its at....I seriously doubt waiting is going to change the way this thing is thinking about working but right now I am all out of ideas!
I guess I could call dell but we all know how dealing with those people can be so I'm hoping I can get somewhere with the help of you fine people here
Anywhoz, this has got to be one of the wierdest PC problems I have run into yet...Free oreo cookies to the 1st one to help me solve this problem!!

Thanks Tews....gonna give that a try now!


P.S. if this works I'll getcha the double stuffed and not the generic ones either...the real deal!

Ok so If I nuke this thing will the disk they send with the laptop get er all back to normal?
(dariks boot and nuke?)