If you just purchased the computer, you should be able to restore it from the restore partition hidden on the computer. Google that model and find out what the code is to do a system restore from the hidden partition, it varies my manuf and model ...OR... make sure your CD/DVD player is the first boot device in the bios and insert the windows 7 restore disc. When it says press any key to boot from disc, hit a key and there you go. Good luck, Ive locked myself out playing with the account settings once, had no way to login, that sucked alot.
Caution - Doing a wipe and reinstall will delete any files you have on there. So be careful.
NOTE: Just because the first part of his question is a no-no, we can be helpful and help him with the second part if he just wants to re-install. Everyone always assumes everyone is a pirate and thief.