I wouldn't even attempt to do that on a computer I intend to return after 15 days, as the only sure way to remove such information is to completely wipe the hard disk with a utility such as DBAN, which nukes all the data off the hard disk.
Wiping the OS off a hard disk you intend to return may upset the retailer.
Even on a computer I own, I would DBAN the drive before I sold it on or gave it away.
Was wondering when i buy a New Comp & use it for few days
Chk my Bank a/c or Buy stuff online with my Credit card
& if i return my comp back (with the 15days) or sell it after 1 yr
whats the Risk of someone knowing my login IDS or bank a/c or credit cards I have used
Or what software do i use to make sure everything is Cleaned off & wont be tracked ?