Our first Q & A of the week comes from Morbiusstrip via the reader feedback page. Remember to try our friendly forums for help too.

Q: I've just assembled the first home computer that I can truly call all mine, rather than belonging to the family or my parents. I'm going to use Windows XP Home as the OS, though I might experiment with installing SUSE 9.1 Linux based on your article. I'm concerned about my data security though. My family has DSL Internet and uses a router, and our main computer always seems to have problems and slowdowns for one reason or another. It was viruses at first, then I formatted it and installed Norton. Now it's just wayyy too slow. I don't want my brand new computer to have the same problems. My question is, can being on the same home network as my parents' computer expose me to whatever nasty software may be living on their computer? I'm going to use antivirus, etc. but I'm not going to take care of their system anymore, so who knows how badly my sister will mess it up... What do I have to do to protect myself properly?

A: Being on the same network as a system infected with viruses or spyware practically assures that your new system will be compromised too, unless you take the proper precautions before you hook yourself up to your home network. For maximum security, you should set your system up with a recently updated antivirus program, an anti-spyware/malware utility like Ad-Aware or Microsoft anti-spyware and a software (personal) firewall like the one included with Windows XP. In addition to this, make sure that you use a password for all user accounts on your computer. This will not only help secure your system, but will also help to protect your *ahem* personal files from your family.

The trick is to update your system without compromising it at the same time. There are two possible ways to go about this. First of all, make sure the Windows XP firewall is active before you connect to the network. If you already have Service Pack 2, it will be on by default. If not, go to 'start/my network places/network connections' and right-click on your network connection. Choose 'properties', then 'advanced' and enable the Windows XP firewall.

Now you can turn off your family's computer for a couple of hours while you connect to the Internet and update your virus checker, anti-spyware software and Windows (in that order). As an alternative, many DSL service providers actually allow more than one IP address for a given connection, so you could possibly get a RJ-45 cable splitter and run your own network cable directly to the DSL modem, bypassing your home network altogether. You'll need to set up your DSL connection on your system to do this, but that's easy enough. You just need to create a new network connection, choose the appropriate options and enter the password and username from your ISP.

For more information, see our 10 essential steps to protecting your PC guide.