Clear all Memory from computer
permanently wipe memory
The 12-inch screen laptop was first sold in mid-2006, and was considered well-equipped, powerful, and ultraportable.
The real issue here is your hard drive/s storage of your personal information. The RAM forgets what it had once you turn off your system completely (shut down). In newer systems that have SSD's instead of HD's it can be a little trickily to clean your files off completely.
The easiest way is to remove the hard drive and drill a few holes through the platters. But in doing so you will have a hard time reselling your system (sans the HD). In that case your next best option here is to get a wiper program to erase forcefully all of the contents by over writing different patterns of data over the unused (erased files) areas of the drive (leaving the system files intact). You could wipe down even the boot files if you have a bootable removable CD/DVD or HD thumb drive. Then restore from the CD/DVD that came with your computer the OS & software it came with.