Description: Secunia Research has discovered a vulnerability in Microsoft Internet Explorer, which can be exploited by malicious people to compromise a user's system. The vulnerability is caused due to an error in the processing of the "createTextRange()" method call applied on a radio button control. This can be exploited by e.g. a malicious web site to corrupt memory in a way, which allows the program flow to be redirected to the heap. Successful exploitation allows execution of arbitrary code. NOTE: Exploit code is publicly available. The vulnerability has been confirmed on a fully patched system with Internet Explorer 6.0 and Microsoft Windows XP SP2. The vulnerability has also been confirmed in Internet Explorer 7 Beta 2 Preview (January edition). Other versions may also be affected. Solution: Disable Active Scripting support.
This is a serious problem, since your computer can be completely taken over. Even if you use another browser like Firefox, Internet Explorer can still be launched to execute this attack.
Disabling active scripting can make many functions of a website stop working, so I advise you to add the ones you visit frequently to your trusted zone. That will let them work while you can still disable scripting for all other sites
In addition to adware, real spyware like keyloggers have been seen in the installs from this exploit. So this is no joke, be warned
Here is a guide that includes pictures on how to disable active scripting and how to add sites to your trusted zone: http://blogs.zdnet.com/Ou/?p=133