How to delete old user account in MyBookLiveDuo (Backup with Time Machine)

I am using an iMac system and back up with Time Machine. Recently my Mac break down and I reset my computer, reinstall to OSX Mavericks, and use a different name as the administrator’s name.

When I try to do backup again, I find that the old record in MyBookLive Duo remains there and the new backup apparently is not replacing them. So MBLD is now occupied by the old data, and the new data are adding up.

How can I delete the old user’s account and all its associated files? Will the data of the old user account and new user account be mixed up and I will delete some of my computer data totally?

Another question is: 
one of my family members is using Time Machine to back up a MacBook Air to MyBookLive Duo and another member is using Smartware to backup 2 computers running Windows 7 to the same MyBookLiveDuo. Will any data delete action affects them?

I am a new user in MBLD, any help will be much approeciated.

To delete the old Time Machine backup you can explore the My Book Live Time Machine backup folder and delete the backup. The Smartware and Time machine backups are saved on different locations. 

Dear Ichigo,

Thanks.

How do I access this TM backup folder? Is it from “Finder” of Mac?  

in Finder, I can go in MyBookLive Duo>Time Machine> Philip’s iMac only. Philip is my name, but my latest account name is not this, and there is no other previous account visible. 

Or should I open it from the Smartware in the right upper corner tab? which open a brower for this address:  http://mybookliveduo.local/UI/.

I read in an earlier e-mail in this community that one has to delete the sparsebundle, is it the way?

Philip