Currently Being ModeratedNov 15, 2012 3:14 AM (in response to cody2210)
if your OS X version is Lion or Mountain Lion:
1. make backup of all your files (that you want to keep)
2. reboot your computer while holding Alt key; keep it holding until all availabel volumes appears on a screen
3. using keyboard, select Recovery HD and boot your computer from this volume.
4. when Mac starts from recovery hd, select disk utility, format your disk, exit disk utility, select reinstall OS X.