Hello anonymous,
to Windows 7 Forums,
There are a few ways to do this;
1. Do a "System Restore" to a point before you tried uninstalling BitDefender and then try to uninstall it again, through Add/Remove.
2. Re-install BitDefender and then try to uninstall it, again, through Add/Remove.
3. Do a "System Restore" or re-install the program and either use the programs uninstall feature or use the following tool and instructions from BitDefender;
Uninstall BitDefender
Hope this helps and keep us posted
Don