"protection" scam?

Do these various anti-virus and anti-spyware software companies deliberately infect PC's with virus and other nasty things and then offer to sell you the "cure"? Much like the old Mafia "protection" scams? I feel suspicious as

my computer began running very badly, I mean crashing, new home pages, locking me out of my control panel etc. then ads began popping up claiming to rid me of the "problems". Now the ads won't go away. They pop up freezing the cursor. It's all very frustrating.

"protection" scam?norton 360

Theyre are some out there like that however theyre are alot of good ones. I espicialy like the ones that run on donations.

I recomend this setup(all are free or offer free versions)

Only run 1 firewall at a time

Avg anti virus

Avg anti spyware

Sunbelt personel firewall

You need those 3, thats like minimum security. These 2 programs are precautionary measure, they block spyware and viruses before they can even think to infect you.

SpywareBlaster

SpywareGuard

Heres a list of some more free anti spywares, that i use and have had no problems with

Ad-ware se

Spybot search and destroy

Super-antispyware

This is a program that will clean up your computer.

cclceaner

Smitfraudfix is another anti spyware\virus program that is quite handy