Where is PHP.exe?

Does any one have any idea how to figure this out? i.e. where is the php.exe file so I can point to it for things outside of WordPress (like my editor)?

I had one thought which was to install a local version of php.exe somewhere else on my machine but then I have to take on the extra task of keeping the two versions of php in sync.

Any suggestion or advice (however small) would be greatly appreciated.

Thanks in advance,
Ben