What is the best way to handle CheckBoxList update/insert?

I have a FormView control with a CheckBoxList control inside. I'm doing all the updates and insert in code behind C#.
For Update process:
1. How do separate the difference between unselected item and new item selected for update?

2. How do I go through all the items in the CheckBoxList control?
For Insert process:
When in the FormView control execution process do I start inserting items into the table? I have three tables (Computer, Software, Tracker). When I insert new comptuers into the Computer table, I also want to insert what software this computer has installed into the Tracker table. The Tracker table requires the ID from of the newly inserted item in the Computer table. So, how do I retrieve this ID during inserting new computer?

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