Am I using adequate security software on my computer?

I have been performing frequent banking trasactions over the web for some years and never had any problems.

I’m currently using my Vista Security suite along with Avast antivirus.

Any suggestions about improving the security of my computer and online transactions?

If i have verizon internet, can I download the verizon security internet suite for free on another computer?

I have verizon internet throughout my house, mostly wireless, and I just got a mac laptop.
On my desktop computer, they installed the verizon security suite software, and I was wondering if I can install the same software onto my mac?

thanks

Japan Criminalizes Computer Malware – Brick House

For example, a cyber attack aimed at an … about going to jail when writing viruses, as opposed to thinking about how much they can profit by stealing from others online. Hopefully this will also lead to hackers and computer experts to use their skills …
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is it bad to have more than one security program on my computer?

this is my dads computer. its has 3gigs of ram and nearly 200gigs of memory..its slow as fuck! one thing i noticed is it has like 4 or 5 different security programs. could this be the cause of it being slow?