In an interview published last Thursday by Computerworld, the developer of a popular freeware antivirus for Windows reveals that the vast majority of infections targeting Windows operating systems affect Windows XP users. The results are briefly summarized in the graph reproduced above, with 74% of rootkit infections on Windows XP compared to just 12% on Windows 7. The figures are in Windows 7's favour considering its increasing usage share at 31%, compared to Windows XP's slipping share at 58%.

Rootkits pose a problem for users due to their ability to mask their presence by hiding at the user, kernel, or even the hardware level of an operating system or computer. Removal of rootkits can be difficult, with some anti-malware suites requiring a on-boot scan or a separate "recovery disc" to remove an infection.