Irritating crashes -- any ideas?

[AlbertLionheart]

My system has been crashing on and off for some time but until recently not so bad as to make me want to do something about it other than make sure i save files on a regular basis.
It just stops - no time so save anything to a log so no clues there.
System: W7 64bit Pro SPI. Quad core 9300 CPU on Gigabyte board. 4Gb RAM
Clues - happens usually when the either of the browsers (IE 9.0.8.112 1642) and FF 6.0.2) are open and almost guaranteed to happen if I have looked at something in Facebook, or other streamed video, and it seems to happen only at the moment the mouse is in use. It happens with both browsers.
Things done so far (all a waste of time):
Reinstalled the OS
Installed latest drivers for everything
Installed the latest DirectX from Micrsosoft.
Checked with Kaspersky as there is an alleged problem with the on-board nVidia network card - got the latest suite for nothing but no result and Kaspersky refuse to comment either way about a problem!

Anyone any ideas?

 

[Tmagic650]

Try removing Kaspersky and go with Microsoft Security Essentials...

 

[AlbertLionheart]

Did that as there is an alleged problem with Kaspersky and the nVidia networj card drivers. Uninstalled Kaspersky and ran the system for a week without it - no improvement.
I am now wondering about the Logitech mouse drivers as it might be a coincidence but I noted it happened when scrolling down web pages. Will try a mouse with electric string, perhaps.

 

[Tmagic650]

Have you gone to the Logitech website and downloaded the latest Setpoint software?

 

[AlbertLionheart]

Yep - did that but it made no difference.
Someone on another forum suggested running IE without Add-ons to see if that made a difference so will try that. The whole process is not helped by the irrregular crashes - two days ago it ran all day without a hitch but yesterday three crashes before the first hour was up!

 

[Tmagic650]

Since you can run the computer all day with out crashing, it might be a bios setting like memory timings or voltage that are off a bit

 

[AlbertLionheart]

Good idea! I checked the voltages for the 750 watt PSU and they are all very close to spec, even when under load.
Today there was a crash after about 30 mins but I also downloaded and instlled the Flash updates for 64bit o/s and touch wood it seems to be OK today and it has been running almost all day.
Thanks for th idea - I'll check if it continues to mess about.