|It seems that there "might" be a recovery partition on the hard disk for this computer (it varies).|
Go here and download the User's Guide PDF (in red near bottom):
Go to pages 91 and 92 of the guide (English part). See from #1 at the end of page 1 to #8 on page 2. This will enable you to determine if the recovery partition is available, and if so it's a case of following the procedure given.
Otherwise it depends just what Disk or Disks came with the computer. If you give us their full titles it might help.
Your post is a little confused by the terminology used. Just to clarify for the future:
Reboot simply means re-starting the computer - what I believe you want is Factory Restore. In your title Memory normally means RAM, what you are wanting to clear is your hard disk.
If by any chance you are too tight for space to proceed then best bet is to type System Restore in the search box, click on it then select a time before you attempted restoring. With luck this might remove the extra install (not 100% sure - never been in quite your situation).
Always pop back and let us know the outcome - thanks