i'll take a crack at this, but anyone feel free to point out anything that may be wrong.

>> I'm a bit confuse about the security of computer because here are too
>> much kinds of security. can anyone tell me what is the different between
>> Network Security, Web Security, Programming Security and Computer security??

You can think of your computer as a house. That would be Computer Security. If anyone was to gain physical access to your house (standing outside) then you would have to think in terms of what they could or could not do to enter or cause damage. You'd want locks on the doors (think passwords). You would want to make sure your house is kept clean of pests and such, so you would hire someone to spray for rodents (think anti spyware software and anti virus).

Network security could be thought of as your neighborhood. Pretend you and your neighbors are all friends, but you still don't want Mr. Jones peeking inside your windows during dinner time. You would want to close the curtains (think network shares and file shares and firewalls) and open them only when you choose to (if at all).

Web security can be thought of as solicitors coming to your door. You'd want signs posted saying " no soliciting " (think AV and email filters). You would want your friends to be able to pop over and share a brew or two, so you would use email though. Your friends would bring things over (think attachments) but sometimes they might get shaken up and cause spillage all over your new hardwood floors and stuff (think virus stuff). You would want AV to help with that. Sometimes your friends would bring their friends over who may be a big dense or rowdy for your tastes. You would want to be able to talk to the friends of your friends first, but they would still be at your house (you could compare this to a web browser [think FIREFOX vs IE] none are perfect, but some are better than others).

I hope this helps and doesnt make it seem complicated. Security itself can be complicated, but you'd want to take it in a step by step approach.

~Halv