Spontaneously reboots

We are confronted with a problem that a laptop spontaneously reboots .

The reboots happen so fast and direct that even though the settings for making a memory.dump are set correctly, only one dump was ever successfully made . This dump shows Tcpip.sys as the cause for the reboot. When NAV19.2.0.10 is removed the reboots disappears.

To ensure that it is not hardware related, we have extensively tested the laptop with a Hiren's BootCD. The various tests shows no errors . The laptop has been undone from all the dust inside and the connectors are checked.

To exclude a virus or malware we have performed the following scans :

Sfc / scannow

Malwarebytes Anti-Malware

SUPERAntiSpyware

Norton Power Eraser

Kaspersky Boot CD

Combofix

All reported a clean health of state for the hard drive with Windows 7 64x Home / 4 GB

All the drivers are up to date.

 

Any suggestions