Hi BIGJON,
Go through the Safety menu on the UO Toolbar, you'll find everything need to clean your system and help protect it.
You're using SpyBot, make sure you're running 1.5.2, have it's TeaTimer function turned on, and... turn on the Advanced mode, go to Setting, scroll down to Web Update, put a check mark in the box to "Display available Beta versions" (this is give you added defintion files for more protection).
Make sure your anti virus program -and- defintions are up to date, if the program is old and/or the defintions subscription is over... replace it, there are plenty of great, free AV products out there.
Whether you're using FF or IE, make sure you're using the latest version... and tighten it up. SpyBot's immunizations will help both browsers (others too, like Opera); but also use something like Comodo's VerificationEngine, McAfee's SiteAdvisor or WOT (anti phishing browser add-ons). Both FF & IE have plenty of add-ons/extensions to help secure your browser.
IM a lot? ZoneAlarm's IMSecure works with most popular IMs, even Trillian. IMSecure doesn't work with Windows Vista yet just so you know.
Email. Please do NOT Outlook Express, but... Outlook 2003 or newer would be ideal. Don't have O2k3+ available... Eudora, Opera Mail and Thunderbird are all in the toolbar (take your choice, their all good). Never use a web email service (Gmail, Hotmail, Yahoo Mail, etc.) for accounts, like UO or anything else you pay through a credit card... use your own ISP for an email addy that is used only for that; never use it on a forum, friends, family, work, or anything else. In 2008 everyone should have at least 3 email accounts: Secret - financial use (don't even tell family), Private - only for family & friends, Public - for public use on the Internet like on non-financial sites, forums, etc.
Yes, like several people here mentioned... more secure passwords are a must. Change them once in a while too, good time to update passwords is just after scanning your system for malware and having found it clean or cleaned it if you did find something. Password managers are a good thing... several in the toolbar.
Good luck.