Trojan "Gendarmerie nationale" not detected

hello,

my computer run with Avast free relaease, but yesterday i have been infected by a Trojan called “Gendarmerie nationale”. I had a lot of difficulties to restore my computer, and i dont understand why Avast didnt detect this because it’s look like an old Trojan in france.

Do you have the infected file yet? You can submit it to virus (at) avast {dot} com
How did you detect you’re infected (which program)?

It’s a ransomware variant,these samples are getting re-packed every hour with custom packers,it is really hard to get detected.Just grab one sample and test it @ virustotal.com.
A useful video,you might want to check http://www.youtube.com/watch?v=_IRoI6FXotg .

i detect the problem because i was unable to start computer. The virus take place of the explorer.exe and display an Warning screen. After some manipulations to take back control, i run Malwarebytes who found and restore it. Something called “disabled.cryptsvc”.
After i check the computer and i was that the automatic update were disabled.
So i re select it and make the update of the computer (one day!!!).

Just a curiosity, was the auto defense module of avast enabled (Troubleshooting tab of settings).

well i guess that the autodefence was activated. I have the french version, might you explain exactly what u mean?

yes it was activated.

i have a look on my computer and i detect that the automatic windows update was activated but never work. i dont understand why! I found something on internet and try it, and now all the updates are down (XP SP3 and all patches). now i guess that my computer is better protected.
Thx for all