I downloaded the Windows 2.5b1, and then tried to 
install following all defaults.

I had previously installed 2.5a2, and it is possible 
that I switched between "install for all users" and 
"install just for me".

The install offered me a finish button, and no protest 
when I clicked it -- but after that, the shortcuts did 
not start python (nor did they protest; they just went 
into never neverland).  Starting python at the command 
line did work.

Reinstall with a repair did not fix anything.

Uninstall, then uninstall 2.5a, then install on a 
"clean" system did work.