umm your HP should have a built in backupHD, atleast all the recent ones dating back to atleast year and a half ago should, I think?. If anything fucks up or you delete anything that you arent supposed to(like suppose you deleted your cd drive) you can reformat, and it installs everything for you. I've done it a few times with my laptop.
I have a pretty dope HP laptop I bought before I went to college a year and a half ago, and it has the backup HD. A few of my friends have HP also, and they all told me they got em too.