Thanks, I'm just back from work so I'll give them a browse in a minute.
edit: ok, the dumps have been blaming system drivers from USBPORT.SYS to TCPIP.sys, stuff that will never cause BSOD's on their own. What's probably happening is another driver is requesting CPU cycles when USBPORT.SYS/whatever has already been scheduled to read from system memory, leaving the pc at a dead-end, resulting in the BSOD. The logs you supplied don't point to any particular device, as they blame USBPORT.sys, TCPIP,sys and DXGMMS1.sys so you'll need to do a bit more work to solve the problem.
Try running a program like Driver Verifier (
link) to see if it picks anything up. If you're lucky, it'll see what driver is causing the CPU interrupts and you can install a newer version/whatever. It doesn't always pick up janky drivers however. Do you have an external USB devices? HDD/Sound card/DAC or something. Three of the five dumps blamed USBPORT.sys, so the problematic device seems to interrupt fairly frequently when your pc needs to do something over USB.