Protecting my laptop

[TEAK36]

I have just purchased a new laptop and am worried about protecting it from intruders.I have ntl broadband installed and will be leaving the laptop connected for long periods.I use Imesh P2P alot,but I have heard stories about people hacking into pc's and doing all sorts of damage.Only last week someone hacked into my brothers pc and did something that meant that everytime he typed in a website address,he got directed to some very nasty porn sites.My laptop has got Norton Anti Virus 2003 pre installed.Is this going to be enough to protect me from unauthorised acess to my pc.

[j2buttonsw]

Keep the virus definitions up-to-date and I would get a software firewall if you are on all the time (blackice defender or zonealarm).

[TEAK36]

Thanks yet again j2buttonsw.Zonealarm was the one I was thinking of downloading.

[jo.sbd]

Just to say that ZoneAlarm is excellent, tho some people find it clashes with other software installed on their pc. Another good (and free) firewall is Sygate, which you can find at: www.download.com