using windows restore function won't restore your computer to "new"
where I assume by "new" you mean the state it was in when you first took it out of the box.
new computers used to ship with "recovery discs" to accomplish this, but it's cheaper for the manufacturer to put the recovery image on a separate partition on your hard drive. when you first get your computer, it is advised to make recovery discs (as a backup). however, you can perform the recovery directly from that partition (but so can someone who steals your laptop!! so you should make the discs and delete the partition and merge it with the main partition).