Hi dannie
It's a friendly way of addressing me

Better than 'what the hell you want now, Jack'
seriously, 'hijack' is a term mostly used for spyware,adware, virus or a trojan that forces your computer to do something you don't want.
Could range from altering your 'home page' in your browser to sending information from your computer to someone for illicit reasons, like personal info such as credid cards, etc.
There is an application called 'HiJack this' that can list the bad 'elements' your computer has installed, and experts at TSG can spot them for you and recomend what to remove. I am not an expert at this, but there are many good people in the TSG security forum that can help.
Good security goes along with installing a good anti virus program and adware/spyware detecting programs, like Adaware and Spybot Search and Destroy.
There are good links and info :
http://forums.techguy.org/t157045.html http://forums.techguy.org/t164246.html http://forums.techguy.org/f54-s.html
(there are 6 stickied threads ^^ worth looking at)
Fire walls are a good thing to check out, also.
smilin' Jack