If you have a Time Machine backup to an external drive (not a Time Capsule), you can boot from that by holding down the option key at startup and selecting it. Otherwise, this:
Follow these instructions for mounting and use the Recovery HD inside Lion to Download the Lion Install files
and then use LionDiskMaker
To make a USB thumb drive of the install files.
Then you can boot from that thumb drive, use Disk Utility to wipe out everything on your hard drive (select the drive name in the partition section and make One partition formatted Mac Extended (Journaled)). And then reinstall Lion.
The install WILL Recreate the Recovery HD partition.
Message was edited by: Shootist007