Thank you both for your suggestions.
I do not believe it to be the sound card - as part of my troubleshooting I disabled my Creative Soundcard and used on-board for a while, but it remained...
I am running a Gigabyte GA-P35-DS3L (rev2.0) GIGABYTE - Support - Motherboard - BIOS - GA-P35-DS3L (rev. 2.0)
Upgrading the BIOS was one of the first things on my list to do - but I had been unable to - however, I managed to get the upgrade utility tool to work last night (horrible @bios thing provided by gigabyte), and upgraded my BIOS from F7 to F8.
I very much hope that this solves my problem - how I am not very optimistic.
Other troubleshooting I have done:
Changed network card and disabled onboard LAN.
Changed sound card to onboard - changed back to card now as problems still there.
Updated all drivers I can see possible.
Running beta drivers for graphics card (as I originally though graphics was the cause).
Rolled-back the chipset drivers for the motherboard.
I really appreciate any suggestions.
Many thanks,
- W