Most of the information here is for Warzone 3.1 and above.
cam26afm transcript
Overview
This report confirms that NEXUS was the cause of The Collapse.File location
sequences.wz / 
sequences / cam2 / 
cam26afm.ogg
Sequence
Analysis indicates that these systems were part of the control system for the NASDA satellites.
It's now certain that NEXUS was responsible for The Collapse.
During the early stages of collapse NASDA technicians switched off the infected systems in order to isolate the spread of NEXUS.
This seems to have prevented the LasSats from firing during the counter-strikes.
The ensuing nuclear magnetic pulses wiped clean large amounts of NASDAs memory banks, shattering it's core processor and sent shock waves blasting through NEXUS.
NEXUS was fried as whole sections of its consciousness were obliterated in the counter-strikes.