I hope, In rerum natura, that the bad boys may have mostly forgotten us and our 98 - not even SE! I've been planning to look into a change to Avast anyway - though, as of this moment, I don't know what their situation is with respect to 98.
My Tiny firewall seems to be going fine. I update AVG every day but only run it once a week, in deference to the geriatric nature of my hard drive. I'm actually considering running it only once a month, while maintaining the daily update.
I update Spybot on Thursdays because they only seem to update it on Wednesdays and I run it now and again.
I run Crap Cleaner, or whatever politically correct moniker it has now, regularly - though perhaps only because its old name tickles me! I usually eliminate approaching 100Mb each week or so.
I've got a couple of newish machines downstairs but I like my 98 so don't even have them plugged in. We'll just have to see what happens, since the bean counters rule all.