Vista random freeze - no corresponding event?

[John]

It is very unlikely that a USB Internet connection would produce an
"operating system not found" error. That error either means your hard
drive
is failing or there is a problem with your motherboard. The random nature
of the problem also points to hardware failure, rather than software.

You can try and troubleshoot this yourself:

http://www.elephantboycomputers.com/page2.html#Hardware_Tshoot

or if this is a laptop under warranty, just call Sony tech support.

Malke

I've had random failures that were software actually. Usually I changed
something like a new version of Firefox, or a new antivirus, or "forcefield"
by Zonealarm. The blue screen of death and data dump were totally
unpredictable; and could reboot the machine. .....at least I hope it's not
hardware....

 

[John]

Are you doing any graphic-intensive work... playing games? Heat can be a
problem. Check for latest USB and NIC drivers.