Cuda debugging crashes cuda win7 crash BSOD

Running Cuda 4.0 on Windows7 using VS2010
I have a sample app using openGL interop.

Stepping into the run kernel step.
On a 32bit machine it leaves behind random dots on the screen which increase with each refresh until the machine has to be rebooted.
On a 64bit machine it instantly blue screens and reboots.

Apart from whatever I’m doing wrong in the CUDA code this isn’t a very productive way to develop!
Is there any debug video driver or safe wrapper that will catch a bad CUDA operation and at least let me find out what I did wrong?