You should be able to make a recovery CD/DVD using the creation tool provided. This should allow you to take the laptop back to the condition it was delivered by HP. However, you would lose all other data you had put onto the laptop yourself and all updates.
Having done this there should be instructions in the manual (installed on the HDD) to recover the partition space. But you would no longer have the ability to create a new backup CD/DVD should you lose or damage that made.
I would suggest you create the CD/DVD, and invest in an external drive and a copy of Acronis True Image or similar. With these you could ensure all your data and the OS were safely backed up. In the event of a drive failure or corruption, you would then have the ability to recover everything on the laptop very quickly.