Do a windows update and patch your programs that need patching if you haven’t already, and then try scanning with Malwarebytes’ Anti-Malware and/or Super Anti-Spyware. (Make sure you get the free version of them!)
Well I would say clearly the windows firewall being disabled by you didn’t work or avast wouldn’t have alerted on the DCOM attacks. That is the task of a firewall an essential part of your system security avast is/should be a fall back measure.
As has been said avast isn’t a firewall (it is just monitoring common attack ports), so you need at the lest the windows firewall enabled and preferably a firewall capable of blocking unauthorised outbound Internet Connections (which the XP firewall can’t do).
Any malware that manages to get past your defences will have free reign to connect to the internet to either download more of the same, pass your personal data (sensitive or otherwise, user names, passwords, keylogger retrieved data, etc.) or open a backdoor to your computer, so outbound protection is essential.
There are many freeware firewalls such as, Comodo (care required now it is a suite not to install the anti-virus element), PCTools Firewall Plus, Online Armor, etc.
See A Forum discussion on free firewalls http://forum.avast.com/index.php?topic=30808.0
See http://www.matousec.com/projects/firewall-challenge/results.php.
Many forum users are using all of the above:
PC Tools Firewall seems to have the least user headaches as it doesn’t seem to be constantly asking the user questions about this and that.
Online Armor for the most parts fine but it has caused some users grief after avast program updates and that is something you have to watch out for.
Comodo is now a suite and you have to do a custom install so as not to install the antivirus element, of all the firewalls listed this seems to be the noisiest in asking questions, depending on settings and elements used, so it could be daunting for those not to familiar with firewalls or their systems.
That looks pretty good. Yes, the PCTools firewall is a free one.
Once the PCTools firewall is installed, turn the Windows firewall off, please. (It may have been turned off by the new firewall, that’s OK.)
I recommend SpywareBlaster, by Javacool. Blocks known bad websites.http://www.javacoolsoftware.com/spywareblaster.html
Mamatu has a good reputation, I haven’t tried it. It is a behaviour blocker antispyware type application. I don’t know if it works well with Avast or not.
EMSI also make A2, the free version I use as a demand scanner. I also recommend MBAM and Superantispyware, recommended above. Very good for a second opinion, or for removing stubborn trojans.
Since you have been running with the Windows firewall off for a time, I recommend running full scans, maybe every 2-3 days, for a while with MBAM, and maybe Avast, just in case. Update MBAM first. If it was me, I’d do this for about 10 days, just to be sure.