PGP FREE: I would think the Windows XP version runs fine on 7 & 8 as well http://www.pgpi.org/products/pgp/versions/freeware/
PGP COMMERCIAL: http://www.symantec.com/encryption
I think it *does* have all the functionality most people need, but the free version is not quite as user friendly as most people are used to. I never tried the commercial one.
I don’t know why people that need encryption don’t use it more. For me, I don’t really need it and figure its use would raise all kinds of red flags, so that’s the trade-off.
The free version for sure, if obtained from a reliable source and verified does not have any backdoors.
Thank you for the answer and the additional comments about PGP. Haven't seen it mentioned in such a long time I wondered if it had been neutralized by the advances of time and technology.
It occurred to me also that using it would act like a red flag. OTOH if I used it for all communications that's all they would have to be suspicious of.