Would PGP be susceptable to the method you used to disable everstrike? Hmmm!
No, because it the program doesn't rely on Windows registry. Once those files are encrypted you can put them anywhere, and you would still need to decrypt them for any sort of access. The encryption does rely on the program, but the way PGP handles passphrase usage is completely different than the origonal application in Everstrike. It's all internally in the program, using keys to unlock data with phassphrases. Thus you would have to attack the file, rather than the program.