Killing processes on Windows 8

I’m debugging plugins on Windows 8 and of course the plugin host (Cubase5.exe) occasionally crashes because of errors in the plugin. On XP or Vista, I could always restart it immediately and continue working. But on Windows 8, even though Cubase appears to close, it is still visible in Task Manager and I cannot kill it by any means. After a minute or two, it disappears by itself. In the mean time, I can’t work because the plugin DLL is still locked by the process.

Does anyone know why this happens on Windows 8? I’ve already tried disabling Automatic Error Reporting but that didn’t help. I’ve tried attaching cdb to Cubase, but I get:

Cannot debug pid 5252, NTSTATUS 0xC0000001
    "{Operation Failed}  The requested operation was unsuccessful."
Debuggee initialization failed, NTSTATUS 0xC0000001
    "{Operation Failed}  The requested operation was unsuccessful."

I tried following the instructions here but it appears this is only possible if I connect a second machine to my computer to debug it remotely.