that some problems with the hard drive have been detected and all you need to do is enable the check so it can check things out. You can enable that by going to "My Computer" and right click on the hard drive in question. Pick the "Properties" tab and then the "Tools" tab. Then click on the "Error Checking" button that says "Check now". You can also get there by starting "Recovery Console" and type CHKDSK /F at the command prompt.
As far as the reinstall goes, if its working, don't mess with it. Unless you really want to reinstall, it will not cause a problem if it is working correctly, to leave it alone.