If, for any reason, you have replaced the original hard drive, the recovery partition no longer exist.
Also, if you, or somene else, unhid that partition to use it for regular storage, the factory reset image is gone.
Some other options:
Reinstall Windows, any version that's compatible with the hardware. If it's the same version, a copy obtained on a torrent site can be used legaly. Normaly, it will reuse your original activation. You can also recover the CD key in several ways, and use it to reactivate the new installation.
Install any distro of Linux.
Both options can erase all user data by reformating, and possibly changing the file system.
Electro, November 2013