have a built in hardware firewall. I assume you a router if you have more than 1 PC on DSL. There just was a Tech Republic article about it. www.techrepublic.com ...Go to the Mfg website and see.
Although ZoneAlarm is dropping support of W9x-ME, download and save the current installation file that is still availible. This old version supposedly will still be availible but no more support-updates. I used an older version for 2 years with no updates, and it worked fine, as far as I know.
Be careful of saying "free-standing" or "standalone" as this means "no installation", "run from folder".
Your comment about "bundled" was good enough.
Also use Google Toolbar for the popup blocker, or other such freeware.
I prefer Adaware spy detector and cleaner. You can have it active along with Spybot. I don't get much or anything with Spybot that is missed by AdAware, but I do vice-versa.
I now prefer Spyware Blaster over Spybot-Immunize for blocking stuff, except it interferred with Norton Utilities on one PC. Be sure to Immunize after each Spybot update. Or "enable all protection" after a Blaster update.