Joe,
This can happen if there is an issue enumerating a device in the computer. Try un-installing, then re-installing with the USB key inserted. This will make sure that it is not an installation issue.
You may also want to try booting from the USB key and running the DOS version. Test the memory, if the memory is bad, PC-Doctor may have problems, it is after all software. This may also tell you if you have a bad piece of hardware.
Laptops can be tricky sometimes. Occasionally the purpose built hardware in them confuses PC-Doctor. Most often this results in the device not being testable not a hang but it is possible. I believe we have a D830 in the lab. If we do I'll fire up Service Center on it and see if there are any issues and get back to you.
-Fred