Blue Screen Of Death when starting 'Day Of Defeat: Source' game

Hi,
 
I've just installed the NIS 2009 Trial and all appeared well until I tried to fire up Day Of Defeat. 
I then got a BSOD with 'IRQL Not Less Or Equal' with the following codes:

0x0000D1 / 0000 / 0002 / 0008 / 0000

The Error Reporter shows this Error Signature:
BCCode : 100000d1     BCP1 : 00000000     BCP2 : 00000002     BCP3 : 00000008
BCP4 : 00000000     OSVer : 5_1_2600     SP : 3_0     Product : 768_1     

 
I've retried a few times and it's the same everytime
 
The Event Viewer has nothing much in it (two System Errors, with scant info)
I've got two minidumps, that I can't read because my Visual Studio trials have run out, and I'm know nothing about Windows anyway ;/
I've scanned the Steam directory (no viruses found) 
I've checked the Valve support forums, nothing there...
 
So... I'll quite happily send the minidumps to anyone who can make head or tail of 'em... does anyone have any suggestions?  This'd be a real deal-breaker for me - if I can't get it to work in the next few hours I'll have to de-install and forget about buying what looks to be a very nice app :(
 
thanks in advance,
 
Ross
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