I'm pretty sure that ResumeThread won't help you, becuase the debugger is highly likely to use the debug interface, and ResumeThread only resumes threads that have been suspended with the corresponding SuspendThread function.
You may be able to detect that there is a debugger running in the system, but realisticly, that would just be an "arms-war", meaning that whatever you prevent, someone will find a way past it.
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Mats
