Python is working for me! I'm not sure why. I mentioned my problems to Bill Rudow, who said that he'd just installed Python on a Windows 7 machine, and it wasn't problematic.
For some reason, when I tried to open Python this time, I got a python shell, which worked, at least to the extent of "Hello World!". I don't know whether I did something different or if all those updates for Windows somehow helped.
Anyway, Bill helped me wrestle the computer to the ground so that I could use the approach described in Learn Python the Hard Way of writing the program in a text editor and having the results appear in a shell.
At my tai chi class, I didn't have knee or ankle problems. This hasn't happened for years.
And Standard & Poor's is being sued by the feds for producing bad ratings which made a considerable contribution to the financial meltdown.
For some reason, the cross-posting from DreamWidth hasn't been working for me.