provide authentication and encryption of a data stream between two systems.
PGP (Pretty Good Privacy) cryptography
SSH (Secure SHell) transmission
SSL (Secure Sockets Layer)
Privoxy http proxy for cookie and advertisement management.
Certificates are available from FreeSSL.com
and CAcert and others.
Anti-Spyware/Adware Software for Windows
This problem is Microsoft-centric. The following progams may be more effective if run from Safe Mode.