Pro Tools Express - static noise

[Graham M Turner]

In December I bought an AVID Fast Track Duo which comes with the Pro Tools Express software, for doing recording of guitar and vocals on my computer at home. I am new to this and have not used the software before, but I have accessed tutorials on Youtube and have got it installed and running on my computer. I have also installed M-Audio AV30 Active Speakers. I have downloaded the latest drivers for the computer equipment.
The problem I am having is that I keep getting random static noise through the speakers or headphones during recording and playback.
I have checked all of the connections, I have switched off the wireless internet and anything else in the room, and I have left my mobile phone in another room to try to eradicate outside sources. The static does not appear on any of the recorded tracks, but does occur randomly when I am trying to listen and record, obliterating any chance of hearing the tracks already recorded.
My computer system is as follows:
OS Microsoft Windows 7 home premium 64-bit
CPU Intel Core i5 750 2.66GHz
MB Gigabyte GA-P55-US3L Intel P55 DDR3 Motherboard
RAM OCZ Platinum 4GB (2x2GB) DDR3 PC3-10666C7 1333MHz Dual Channel kit
Graphics Palit GeForce 210 512MB DDR2 PCI-Express Graphics card
Hard Drive Samsung Spinpoint F3 1TB SATA-II 32MB cache
PSU OCZ Z-Series 550w SLI Certified power supply

Then I have a Samsung monitor, a DVD player, a couple of external hard discs for storage/back up, keyboard, mouse, webcam, Canon scanner, Epson printer
as periferals.

Does anyone have any experience of a similar problem and if so any advice on how to fix it? I am wondering if the Fast Track Duo box is faulty in any way.

I am getting very frustated and have spent many hours on trying to solve this problem so far to no avail.
Thanks, Graham