This will show you how to burn the downloaded osx lion to a usb flash drive so that you can do a fresh install.

  • download lion from the app store.
  • right click the downloaded file
  • click ‘show package contents’
  • go to contents > sharedsupport
  • right click on the installesd.dmg
  • copy it, and paste it on your desktop
  • insert flash drive [8gb recommended]
  • open disk uility
  • click on your flash drive in the left column and click ‘erase’
  • dont do it on your harddrive.

once the usb drive is erased and formatted [as a mac partition]

  • drag the installesd.dmg to the left column of disk utility
  • then click on it in the disk utility
  • goto restore
  • as source drag the installesd.dmg to that box
  • as destination drag the freshly formatted usb drives partition
  • hit ok.

enjoy your lion install flash drive :D