Windows' firewall does not block outgoing connections, so this will not be the cause of the problem, but McAfee security suite does include a firewall, so this might be causing the problem.
The McAfee Anti-virus may well also conflict with avast!- both will try to check e-mail, so this may be causing the problem with the outlook/exchange subsystem. You will need to uninstall this.
You can replace McAfee firewall with the free version of Zone Alarm, Sunbelt firewall or Comodo firewall, if you want to continue using a third party firewall (recommended!).
CiD popups? What are these? If you are having problems with pop-ups, follow this advice:
Uninstall avast!
Uninstall all McAfee components.
Reinstall and update avast!
Download, install and update all these programs.
AVG Anti-Spyware (Requires Win2k/XP)
a-Squared FreeAd-AwareSpybot Search & DestroyGrab a copy of Zone Alarm Free, it's probably the most user friendly, or the firewall of your choice:
http://www.zonealarm.com/store/content/company/products/znalm/freeDownload.jspDisconnect from the internet (pull the plug).
Run a boot time scan with avast! Right click the scanner screen, select 'schedule a boot time scan' and reboot when requested.
Run scans with the programs above.
Install Zone Alarm free and reconnect to the internet.
Don't forget the info about ZA pop-ups here:
http://www.zonealarm.com/store/content/support/zasc/gettingStarted.jsp?anchor=alerts&lid=zasupp_uEDIT: typos.