Can't run python on windows anymore

First make sure that python.exe exists in the given directory and that its not a zero-length file. More likely though is that you installed the wrong version of python. Make sure you download and install the x86 version as it will work on both 64-bit and x86 systems. Do a full uninstall and install python via the Windows x86 MSI installer.

Edit:

If this doesn't work please provide more information on which specific Windows 10 version you are running and which python installer you are using.

Edit 2:

You can also get more information from the Windows Event Log