Remoc's trying to save you some pain, by suggesting you get of CA He's not suggesting that you run with no protection... just that maybe there are better programs out there & that some of those could be freeware.

It's up to you whether you use it or not, but there are suggestions that it's not that good... check out the links below for some examples.
PC World - Review of the Computer Associates CA Internet Security Suite Plus 2008 Antivirus and Security
CA Internet Security Suite 2007 Review - Not Enough Bang for your Buck
Security Suites 2008 - CA Internet Security Suite Plus 2008 - Full Review - Reviews by PC Magazine
Review: CA Internet Security Suite Plus 2008 - New Zealand's source for technology news on Stuff.co.nz

Are you making sure to scan all files that you download with your AV, before opening them? There are heaps of infected files being shared & you do have to be really careful. It's so easy to download a nasty.
* WARNING: Viruses on network you should be aware of ! *
If you're seeing popups (apart from Pro nags etc) then it might be wise to scan for spyware/adware.

It shouldn't matter whether you're using LW basic or Pro... both connect to the same network & neither have security features.