I have version 4.8 Home edition of avast!. Operating System is Windows XP Media edition.
I mostly use Mozilla Firefox to browse - but sometimes use Internet Explorer. My firewall is ZoneAlarm free edition.
Besides running malware bytes-anti-malware on my system, what else should I be doing to stay safe?
Thank you.
I would suggest also SUPERantispyware On-Demand only in free version.
Spywareblaster Don’t install this until you are clean. This is a passive immunisation tool to prevent malicious, activeX, BHOs, sites being able to do the likes of drive by installs of malware. There is no resource overhead other than when you periodically check for updates, which you then apply and close the program.
I would also suggest a visit to this site, which scans your system for out of date programs that have patches to close vulnerabilities, http://secunia.com/software_inspector/.
Hi…
In addition to what David has suggestion and if you have the additional system resources to spare (meaning that the inclusion of this software will not bog or slow down your system excessively,) I would recommend one of the following antispyware programs that includes realtime scanning capabilities…
http://www.microsoft.com/windows/products/winfamily/defender/default.mspx
http://www.spywareterminator.com/
Should you not understand the configuration options or what to choose, please post and let us know. Both programs, I believe, have certain options checked automatically upon installation, so you can go with the default settings if you choose. 
May God Bless you!
Get yourself the Noscript and the Adblockplus add-ons for Firefox. The former can protect from drive-by downloads. Can make browsing a little annoying at times, by blocking some functionality required for web pages to display, and links within to work correctly. This can be easily overridden on a case-by-case basis.
Try the MVPS hosts file. http://www.mvps.org/winhelp2002/hosts.htm Hostsman http://www.abelhadigital.com/ is an easy application to manage and update it. Similar to SpywareBlaster, mentioned above, in that it blocks known bad sites from loading. The first page linked above gives information and complete instructions/faq’s etc.
Endorse SpywareBlaster, and Superantispyware.
Also strongly endorse the Secunia application. I’m using the downloadable version, called the PSI (personal software inspector, I think.) Monitors a large database of different applications for updates/known vulnerabilities.
I use Threatfire, a behavior blocker, and it seems to run nicely alongside Avast. Can prevent system changes being made by what’s called zero day malware. (Too new for scanners to detect, yet.) Will also sometimes detect legitimate changes made when installing some programs, so if you trust/know the program, you need to allow the change.
Last but not least, have a routine of some kind for backing up important files, either to another hard drive or some reliable and secure online storage.
Like WebShots downloads, for instance.
How?
Don’t forget to disable DNS Service as required, or you will have conflicts.
How is it working with Firefox extensions (update and installation) nowadays?
Use on line backup with Mozy (check my signature) 