You can delete your account on the settings page of your user account. Please note, as soon as you delete your account, your cloud computer will be erased. You will forfeit the remainder of your balance in your cloud account. The account deletion has a grace period of 30 days for which you can change your mind, but after that point, all of your other data will be erased.
Visit the Account section of settings. Clicking this link will open a webpage that you may need to log into in order to manage your account.
Click Deactivate Your Account and follow the instructions there at the bottom of the page.