Browser hijacking is probably the most dangerous form of "malware" because it allows an attacker to steal your online identity.

In June of 2009, cyber criminals stole $415,000 from Bullitt County Kentucky by infecting the county treasurer's PC, creating fake employees, and wiring funds to bank accounts abroad. Microsoft's Internet Explorer is the software most susceptible to this type of attack.

The most foolproof way to prevent hijackers from infecting your PC is to use a "read only" operating system, or "Live CD" that does not open your hard drive, such as Ubuntu or Knoppix, for your online banking transactions.

In a hard-drive, the recording heads literally "fly: on a cushion of air over the surface of the discs. A "crash" is when one of the heads comes in contact with the disc, physically gouging and destroying it's surface. The hard-drive is the most likely part to fail, as it contains moving parts that spin at well over 5,000 rpm.
Most computer failures are not really "crashes", but are more likely the result of "bugs" or "holes" in the operating system. Computers, contrary to most people's experience, should run for several years without fail and without having to reboot them on a regular basis.