Further to a previous request, I have now figured out how to open MMC and create a folder for IP Security Policies on Local Computer.

It then gives three entries:
- Client (Respond Only)
- Secure Server (Require Security)
- Server (Request Security)

So from this point what are the steps involved (and settings to use) to set the IPSEC filtering under Windows XP so that only internet access / emails are blocked (yet I can still access a network printer and share files with other computers on my home network)?

Thanks in advance.

IPSEC is for encrypting traffic across a network, it has nothing to do with port blocking.

To prevent a computer from accessing the web browsing or email, implement a Firewall which blocks ports 80, 443, 25, and 110. Better yet, simply use your firewall to block all traffic that didn't originate on your private network. This can be done via a software firewall on the PC, or with your router (depending on the specific one you have).

IPSec is perfecly valid to use for port blocking. Instead of specifying how the data should be encrypted, you just tell it to block it