Forum users at Broadband Reports have posted some problems with Microsoft’s new patch for Vista. The
KB925902 patch, which was supposed to fix vulnerabilities including the cursor exploit, is reportedly creating issues including stopping antivirus software such as AVG and F-Secure loading correctly, causing false positives of a Trojan, and even preventing users booting entirely. Although this isn’t yet a widely documented problem, it may be best to delay patching Vista until the matter becomes a little clearer. Apparently the news poster at neowin.net also experienced this problem, with one of the two computers he installed the patch on failing to boot.
Source: Broadband Reports via neowin.net