Source -Windows 7 PCs Stop Responding After Clean Install on Second Boot.
A computer on which Windows 7 has been deployed via a clean install can stop responding completely after the second restart. This issue also affects Windows Server 2008 R2, Microsoft informed, and is related to the 1394 bus driver. According to the Redmond company, machines running Windows 7 or Windows Server 2008 R2 can also stop responding when customers enable or install a 1394 device. The IEEE 1394 is a serial bus interface standard most known by the following brands FireWire (Apple), i.LINK (Sony), and Lynx (Texas Instruments).
Windows 7 PCs Stop Responding After Clean Install on Second Boot - Because of the 1394 bus driver - Softpedia