BitDefender came close to a PC Advisor Gold Award. It did an excellent job of detecting malware, with a 96 percent catch rate. And it ranked second in our proactive-detection tests, behind Eset's NOD32, using month-old signature files, nabbing 61 percent of new malware samples. And at £26 it's one of the least-expensive apps around.

The program was badly hamstrung by serious slowdowns in our application performance tests, however. One Firefox test, for example, which loads a large number of different web pages, took three times longer with BitDefender than with any similar program we've tested. The company says the slowdown was due to a known bug in the Vista version and that a future BitDefender update will fix it.

In addition, although it excelled at detection, BitDefender was less adept at disinfection. It successfully cleaned just 13 out of 22 items, missing one malware file and both of the changes to the Hosts file.

BitDefender also had a high false-positive rate, incorrectly labelling 14 harmless files (out of a total of 20,000) as malware.

On the plus side, BitDefender has a well-designed interface, with a slider bar in the main window that provides an easy way to modify the protection levels, and clearly marked icons for launching full scans or setting up custom scans. It was also the only product to offer round-the-clock phone support, with easy-to-find phone numbers and support email addresses listed in the Help section of the application.

By default, the program runs a full-system scan daily. It scans email traffic on the POP3 and SMTP protocols and integrates nicely with Microsoft Outlook, Outlook Express, and Windows Mail (on Vista) for antispam filtering. BitDefender has a basic level of instant-messaging protection, but unfortunately it doesn't scan HTTP traffic by default to identify web-borne threats, so you'll need to turn on that capability yourself.

A unique 'privacy guard' feature detects when personal information such as a credit card or passport details are being stolen from a computer without you first having to tell the program what those numbers are. BitDefender automatically disabled Vista's built-in Windows Defender antispyware utility, however.

Test results and verdict on the next page >

Click here for the latest PC security news, reviews and downloads