This is a pretty tiny bug..

The test_reg_class test in test_msvc9compiler.py assumes that there is a
Notepad registry key on Windows systems.  That appears to be false until
Notepad is run the very first time.  I ran into this setting up a build
slave VM, where I never had the need to run Notepad.

I guess it's pretty rare for Notepad not to be run eventually, but
clearly the comments in the test saying the key is always present is
inaccurate, and perhaps a different key should be chosen or at least
have the test not fail if the key is missing.

It also appears that Windows 7 doesn't have that key even after Notepad
is run.