Spring doesn't merely bring flowers and yummy mangoes -- it just as surely comes accompanied by a rash of antivirus software releases. Trend Micro's Internet Security Pro is the latest suite to hit the market, and this release, which drops the 'PC-Cillin' tag, brings with it an exhaustive feature list.

Single-pass scan for viruses, suspicious software, Windows security flaws and other threats, strong protection against unauthorised changes, network management tools, Pro services and a tweaked interface are all included in Trend Micro Internet Security Pro.

The 'Pro' version distinguishes it from a slightly cheaper standard version of Trend Micro Internet Security. While both offer the usual antivirus, spam, spyware and phishing, plus firewall, parental and privacy controls, Pro also includes Remote File Lock, a password-protected vault that can be remotely 'sealed' should you lose your PC, and System Tuner, a less ruthless version of CCleaner, which frees up disk space and cleans out dud registry entries.

Last but not least, Trend Micro Internet Security Pro's Transaction Protector keeps a watchful eye on Wi-Fi networks and encrypts your keystrokes. In line with its Symantec and McAfee rivals, Internet Security Pro can be installed on up to three PCs, so it represents decent value.

Trend Micro Internet Security Pro, like many other antimalware products, relies on heuristics to provide continuous protection, although here the technology goes by the name of PIB (Proactive Intrusion Blocking).

Trend Micro works unobtrusively in the background, automatically deciding whether or not a pattern of behaviour is suspicious. Its malware detection credentials remain high -- Trend Micro Internet Security Pro has a Virus Bulletin's VB100 award and is certified by both ICSA Labs and by West Coast Labs for virus detection and virus removal.

West Coast Labs has also awarded Trend Micro Internet Security Pro a Checkmark certification for detection of spyware, Trojan horses and malware.

Spyware protection is also much improved. Trend Micro Internet Security Pro scans every file upon access, and checks all incoming and outgoing e-mail for viruses. You can also scan Web-based e-mail attachments, but you have to turn on this feature. A number of features like this are turned off by default, which probably isn't a good idea.

On the spam front, Trend Micro Internet Security Pro adds a toolbar to Outlook, Outlook Express and Windows Mail -- it does work for Thunderbird but it doesn't add a toolbar. The Microsoft e-mail clients also get the exclusive benefit of automatically adding addresses from your address book to an e-mail white list, a thoughtful feature. Spam detection remains good -- it had no trouble identifying spam attracted to our honey-pot account.

Many irritations of the previous release have been addressed. Before, there were separate scans for viruses and spyware, but now both are conducted simultaneously. Combining the two has reduced Trend Micro Internet Security Pro's system overhead, so you shouldn't notice your PC slowing down too much or be bothered by prolonged scan speeds either.

However, it does take an age to load Trend Micro Internet Security Pro when you boot your PC, and updating can also be a test of endurance -- during one update, it actually disabled itself, so that Windows XP's Security Center popped up a warning to this effect, which is a little alarming.

Instant Message scanning is no longer confined to MSN Messenger, and most popular IM clients are now supported. The Trend Micro Internet Security Pro firewall is much improved over last year's model --previously it would bombard you with pop-ups whenever you launched a new program, even if it was benign. Now, it decides for you whether to permit Internet connectivity. The same can be said about its PIB heuristics -- it operates less intrusively than before, and won't warn you about innocent programs like the previous version.

A long-standing problem with the resilience of the Trend Micro Internet Security Pro firewall against manipulation by malware remains, however.