I swear to freaking god...

I almost started shouting from the roof tops. I took Harley's suggestion, uninstalled CCC, driver swept, reinstalled 11.1. Tested a couple MW WUs, and they completed successfully. Woohoo!

Decided to test a couple Collatz WUs next, and the problem came back - driver death.

Did I mention I reinstalled Winders today? Bah!

Ok. Going to try the Fire$torm laundry list of activities now, adding in uninstalling .NET and reinstalling it. And punching a baby. That goes on the list too...