What can I do to solve this problem definitively, once I ask for AVAST removing it but in the on the next boot it returns?
I the anti-spyware SPYBOT: Serach and Destry installed and it advise to me that the virus attempted to change the windows register but it didn’t allow.
Do you use Win XP? If so, do you have the system restore function turned on? If you do, you may have to turn off the system restore as an infection can hide in it and will always return when you reboot. It may be worth a try to turn off the restore system, let your virus removal program do what it can. Then reboot the pc, turn the system restore system back on and let the virii be purged from the system restore. Then, I would suggest leaving the system restore function turned off.
Please follow Neal’s advice plus the following generic advice:
Please ensure you have done a thorough scan with avast!, preferably a boot time scan. (This doesn’t work in Win 98: if you have this OS, boot into safe mode before scanning- hit F8 while booting.)
Right click the avast! globe and select Start avast! Antivirus.
avast! will do a memory scan: if it find the worm in memory, it will prompt you to do a boot time scan: accept this and reboot.
If avast! doesn’t find anything in memory, schedule a boot time scan. (Click the button at the top left of the avast! silver console and select Schedule boot time scan from the drop-down menu.)
The anti-Trojan program Ewido is also worth trying: it has a free version: