internet use g3-400

I am a g4 user in the studio but has been a peecee user for the internet--untill i started getting about 100 spywares a day and multiple viruses and the changing of the home page---made it unuseful---so I saw where alot of people said macs just wont get that --right now im using internet explorer for the browser on my g3...yes I will admit I look at some adult material ( im only human ) but even ebay was giving me a bunch of spyware stuff...do I need to protect my mac from that stuff --and what browser should i use---thanks stix