Consecutive BSODs 3 times in a row. How?

I was playing around with some kernels of mine, and apparently a bug (from my stuff of course) was triggered and the driver died. But vista didn’t restart the driver, I just got a … nice restart. And on restart, on windows initialization I got again BSOD. And after one more restart, again BSOD at windows initialization. And then it was alright. Unfortunately there’s no dump log in c:\Windows\Minidump so I can’t check the error codes :(

My question is :
How did I manage to break it THAT hard? I guess some programming errors are worse than others, so I’m wondering which types of errors can potentially cause a driver restart. Or the dreaded persistent screen artifacts.

Card : single 9800 GTX
Drivers : 196.21
Cuda 2.3
Vista 32-bit

Thanks,
Babis