My avast just detected a virus in the name of Win32:Agent-QJ [Trj]. My selected action was to delete it but after doing so i found out that my windows firewall is no longer working anymore and in no way i could get it back on even by manually activating it. It goes something like this when i tried to activate it, “Due to unidentified problem, windows cannot display firewalls settings.” Besides, i even tried various programs like spybot and Ewido but doesnt solve the problem at all. Help would be much appreciated if i could get my system back to what it was again 
Hi :
You just discovered why the PREFERRED action of anything
Avast detects is to "move it to Chest"; do NOT delete as
a 1st choice. And since a "trojan" was detected, we usually
recommend the use of "Ewido" from www.ewido.net/en
( assuming your OS is Win XP or Win 2000 ) for "dealing"
with trojans, worms, generic dialers, etc . This good &
FREE program has all its features for a 14- day trial .
As to your firewall, you would be better off if you had a
"real" firewall and there are lots of good FREE ones
available, such as Zone Alarm and Sygate .
i had “move to chest” as my 1st choice though but for some reasons the move wasnt successful so i had no choice but to choose delete. Even when i already chose delete and avast wasnt better to pick up the virus again, my gut feeling still tells me that its still in my system if not my windows firewall would start working again already. So are there any cleaners out there that specifically seeks out this virus and destroys it totally? Help appreciated.
Some trojans [Trj] cannot be repaired or even moved to Chest. Some of them, you must delete the entire file (infected).
If a virus is replicant (coming and coming again), you should: 1) disable System Restore; 2) Clean your temporary files; 3) schedule a boot time scanning with avast; 4) use a-squared or ewido (trojan removers).
Both programs did not help at all. This shit is killing me >:(
But did you follow steps 1, 2 and 3 as well or not?
Hi Deathcoffin,
This may well be a rootkit infection. See here:
http://forum.avast.com/index.php?topic=20994.0
Delete any hidden files with BlackLight then run another Ewido scan.
Once Windows firewall has come down, it’s almost impossible to put it up again with 100% guarantee of security: you would be better off downloading a good third-party fireall like Zone Alarm or Kerio.
Edit: I found the write-up from Trend Micro:
http://www.trendmicro.com/vinfo/virusencyclo/default5.asp?VName=TROJ_AGENT.QJ&VSect=Sn
Seems this one is pretty routine to remove and doesn’t use a rootkit. However, something has made changes to the registry to bring down Windows firewall. What I said above still applies.
All steps in sequence
Thanks guys i managed to get the virus out of my system though windows firewall was still down when i did it, i search the web on how to repair windows firewall when it was downed by a virus so i got it repaired and its back on again. Anyways thanks for the help though. Appreciated.
Once Windows firewall has come down, it's almost impossible to put it up again with 100% guarantee of security: you would be better off downloading a good third-party fireall like Zone Alarm or Kerio.
I’d been searching round for the article I got this information from, and finally found it:
http://www.pcworld.com/news/article/0,aid,122927,00.asp
(Via SpywareInfo.)
http://www.spywareinfo.com/newsletter/archives/2005/oct27.php#winfirewall
Deathcoffin, glad that you are on the way to resolving your problems.
You might want to change your avatar for another, resize or use this one. We try to keep avatars around 100 X 100 for those who don’t have high resolution monitors.
Thanks for the resize man 
No problem, a belated welcome to the forums.