As soon as friends or acquaintances find out about the job I do then it turns into a Doctors waiting room of people asking questions around the various ailments on their Computer. To be honest I don't really mind and usually advise them the best I can. Plus the offer of a bottle of wine to come and look at their machine usually helps !.
However there are some things you can do to ensure your machine is well protected.
1. Ensure you install a good Virus Checker. There are some great ones out there and there. Plus of course OneCare does a really good job too.
2. Ensure you run on a regular basis anti spyware software. Again OneCare is great for this, but other great ones are Windows Defender, AVG, and AdWare
3. ALWAYS be suspicious about emails from any Retail Environment,Bank, Ebay etc etc. It is always better to err on the side of caution. If it is that important they need your details they will contact you by phone, or snail mail.
4. Always engage common - sense. An British Expression says " You don't get ought for Nout". Think first act later.