|Be careful with the System Restore Idea unless you do not care about any files you stored on your drive.|
It sounds like one of your partitions was not formatted. Which drive do you have as your bootable partition? I am guessing it is not C: unless you are booting from a CD.
You can find all of this information under Computer Management by Right-Clicking "My Computer" in your start menu and then choosing "Manage" on the menu. Then go down to Disk Management. Here you can see all of your partitions.
Tell us what it says to the right of C:. It should say
"Healthy (System, Boot, ...)"
If not let us know and also let us know which drive does say this because we may need to switch drive letters.