I have Norton 2003 version which was not updated till date. Today if I download intelligent updater 01 Nov 2007 and update Norton 2003; Will it detect Viruses between 2003 to 31 Oct 2007??

Yes. Run a complete scan of your hard drive after updating. Antivirus software always scans using the latest set of virus definitions.

Vasily

I do NOT recommend Norton Anti Virus. It sinks its hooks too deeply into the operating system often causing other problems. I would recommend you switch to TrendMicro's PC-cillan.

But the way a/v utilities work is by detecting viral signatures. The updates you get are updates to the signature file. Such updates are cumulative.