Most people that browse the Internet use "Internet Explorer" (IE); last time I went through the the statistics of my web sites 89% of viewers used this program.

Unfortunately because it is so highly used (and made by Microsoft) it is a huge target for hackers and malicious software.  Simply by visiting some web sites programs can be installed into IE, thus allowing hackers access to your computer!

The best way to stop this is by simply installing different software to view the Internet with; for this I personally use Firefox.