Microsoft warned of an flaw in Windows 7 64-bit that can allow an attacker to cause your system to stop responding and restart. They are currently working on a fix, but in the meantime, you can disable Aero Glass to keep safe from this attack. Of course, using common sense, you could probably stay away from this attack in the wild by staying away from questionable websites.

Microsoft admitted that the Canonical Display Driver vulnerability, which stems from improperly parsed information copied from user mode to kernel mode, could ostensibly allow remote code execution attacks, although it was more likely that an attacker would exploit the flaw to cause a user’s system to stop responding followed by an automatic restart.