BSOD on Windows 7 64 bit. Can someone diagnose this?

I recently reinstalled windows on my pc in hope this would fix my BSOD problem, it hasn't and has recently crashed again, I was wondering if anyone could help me troubleshoot this and find out what's wrong?

I have uploaded the minidump file here : http://dl.dropbox.com/u/33970527/021412-51605-01.dmp

I have also uploaded a screenshot of the BSOD here:

and the debug info using WhoCrashed:

Whocrashed info

Crash dump directory: C:\Windows\Minidump

Crash dumps are enabled on your computer.

On Tue 14/02/2012 15:58:35 GMT your computer crashed crash dump file:
C:\Windows\Minidump\021412-51605-01.dmp This was probably caused by
the following module: ntoskrnl.exe (nt+0x705C0) Bugcheck code: 0xD1
(0xCF434084, 0x2, 0x0, 0xFFFFF88004C9E4B7) Error:
DRIVER_IRQL_NOT_LESS_OR_EQUAL file path:
C:\Windows\system32\ntoskrnl.exe product: Microsoft® Windows®
Operating System company: Microsoft Corporation description: NT Kernel
& System Bug check description: This indicates that a kernel-mode
driver attempted to access pageable memory at a process IRQL that was
too high. This appears to be a typical software driver bug and is not
likely to be caused by a hardware problem. The crash took place in
the Windows kernel. Possibly this problem is caused by another driver
which cannot be identified at this time.

On Tue 14/02/2012 15:58:35 GMT your computer crashed crash dump file:
C:\Windows\memory.dmp This was probably caused by the following
module: usbohci.sys (usbohci+0x24B7) Bugcheck code: 0xD1 (0xCF434084,
0x2, 0x0, 0xFFFFF88004C9E4B7) Error: DRIVER_IRQL_NOT_LESS_OR_EQUAL
file path: C:\Windows\system32\drivers\usbohci.sys product: Microsoft®
Windows® Operating System company: Microsoft Corporation description:
OHCI USB Miniport Driver Bug check description: This indicates that a
kernel-mode driver attempted to access pageable memory at a process
IRQL that was too high. This appears to be a typical software driver
bug and is not likely to be caused by a hardware problem. The crash
took place in a standard Microsoft module. Your system configuration
may be incorrect. Possibly this problem is caused by another driver on
your system which cannot be identified at this time.

________________________________________ Conclusion

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2 crash dumps have been found and analyzed. Read the topic general
suggestions for troubleshooting system crashes for more information.

Note that it's not always possible to state with certainty whether a
reported driver is actually responsible for crashing your system or
that the root cause is in another module. Nonetheless it's suggested
you look for updates for the products that these drivers belong to and
regularly visit Windows update or enable automatic updates for
Windows. In case a piece of malfunctioning hardware is causing
trouble, a search with Google on the bug check errors together with
the model name and brand of your computer may help you investigate
this further.

I have no idea what could be causing this and it appears to be happening at random. I was hoping someone could help me out. I can upload any other info you need.

My system is custom built from pcspecialist and I've had the hardware checked recently, however that doesn't completely rule that out as the cause of the problem. also I have very few programs installed at the moment but that doesn't completely rule out a recently installed programmes.