This may scare you but it is the truth that recently, a vulnerability in Internet Explorer 8 is discovered. The main cause is a code used in Google hack which may exploit your Internet Explorer in public. The code is now publicly published over the Internet and is now visible. This vulnerability may allow the attacker to use your system and gain your system rights.
This attack is more easier on old systems with less security or with windows like Windows XP.
Microsoft has said that a fix for this vulnerability will be available soon. Microsoft has highly advised to the users to use any alternative like Google Chrome or Firefox until a fix is available.