In QC 9.2 there is a specific status called Open, that actually depends on the customization of the defect module in QC by your project admin.
He may define the defect workflow as per your company process where open bug may not be there.

New Bug can be defined as the bug which was found freshly and had been logged with status as New.This is the Intail state of a Bug

Open bug can be defined as in such way that a bug which was in closed or terminated state can be set to status open and can be assigned back to a developer for solving.
This is one of the example

Open bug may also be treated as a state next to New Bug.that means the bug had been identified as a valid one and had been assigned to person in active state.