There are enough free security tools out there not to have to pay anything for protecting your PC. See [broken link removed] for recommendations for example.
as clubman said no need to spend money on this. There are a few basic one i would recommend to have on your PC. Adware, spkybot, AVG free and zonealarm firewall. Also i would recommend using Mozilla firefox as your internet browser, it stops pop ups etc..If you need any further details let me know
Had the paid version of Ad aware on the computer in my last job.
It didnt slow down the computer. It came with an active guard which stopped ads downloading onto your computer. The free version doesnt come with this and you need to scan and then remove these ads after they have gotten onto your computer
PS Have just started using FireFox
it doesnt always block pop ups for me as IE didand yes I have the option selected
search the mozilla [broken link removed] library for adblock and noscript to enhance the default blocker, cant remember the last time I had a popup since i put these on
while youre at it, search these following extensions that I find useful
stumbleupon -- random page selector based on interests, great for killing time
crash recovery -- if firefox goes down, it brings tabs back to before crash
tab X -- puts an X on each tab rather then having one allllll the way over on the right
Also search [broken link removed] for "littletheme", lets you get more mozilla for your money