Generally speaking, hackers try to take control of a computer by infecting a computer with malicious software. However, it appears that there is another way that hackers might want to get access to our computers, namely, by hacking microprocessors. Last year researchers from the University of Illinois altered a computer chip to grant attackers back-door access to a computer. If hackers would decide to do this, detecting what is wrong with the computer would be virtually impossible. The way it technically works is that malicious firmware would be injected into the chipís memory that would allow the attacker to log into the machine as if he were a legitimate user. For this type of attack to work, the hacker or his associates would have to get physical access to the processor which fortunately is unlikely. However, the possibility still exists, and it is quite scary that any one of us could be using such hardware.
Of course, it is a lot easier to defend from software threats such as viruses and spyware. In order to be well protected you should be simply using a safe browser, and have an up-to-date antivirus and anti-spyware program. Firefox is generally considered to be the safest browser so keep that in mind.