C Murdoch asks: I have a small home network set up with XP pro. My network is a workgroup not a domain. The network consists of an ADSL D-link 504 router, two desktop PCs and a wireless access point. One notebook and a PSP gamepad connect to the network via the access point.

I have set all the security settings in the router and access point. I have also turned off DHCP and assigned static IP addresses to each machine. Also I have set the access point to allow access only from the MAC addresses of the notebook and the PSP.

I have antivirus software, zone alarm, and antispyware software installed on every machine. However one of the desktops uses the free Grisoft and the free Spybot – this is my son's PC. The notebook and the other PC have commercial antivirus and -spyware installed.

My concern is over filesharing. I take the notebook to work and synchronise a lot of files within it with one of the desktops, and so have filesharing set on some folders. These are therefore accessible from my son's system. How can I stop this? I want only the default shared folder to be accessible from his system as I feel that it may be a weak link in my security.

Pete replies:

You can fine-tune the permissions on the folders you wish to restrict access to yourself.

Right-click on the folder, select Sharing and Security. Click Permissions and add yourself with full access and deny access to others.