Still using Windows 98? I'd seriously think about upgrading to XP if I was you - if you ever connect your machine to the Internet, that is. Microsoft is currently defending its decision not to patch a critical security flaw in Windows 98, and support for the operating system officially ends in less than a month's time.

Recently, a vulnerability was discovered in Windows Explorer and the way it handles Component Object Model objects, which could have been exploited by malicious hackers. Updates correcting the flaw were issued for Windows 2000, XP and Windows Server 2003, but Windows 98 remains unfixed. Why? Well it appears that Microsoft has just left the OS behind, but of course they had something more tolerable to say on the matter.

"Due to these fundamental differences, these changes would require re-engineering a significant amount of a critical core component of the operating system," Christopher Budd, Microsoft Response Center security program manager, said.

"After extensive investigation, Microsoft has found that it is not feasible to make the extensive changes necessary ... to eliminate the vulnerability," he said.

Windows 98 is not the only version of Windows that's on security death row - Microsoft support for Windows XP SP1 will expire on October 11 2006, forcing users of that OS to upgrade to service pack 2 if they are to remain secure.